13. Hazard to life

Introduction

Background

13.1 This section of the EIA presents a summary of the analysis and findings of the Hazard to Life Assessment (also referred as Quantitative Risk Assessment (QRA)) undertaken for the proposed Hong Kong (HK) Section of the Guangzhou-Shenzhen-Hong Kong Express Rail Link (XRL) project. This is a cross-boundary transport infrastructure project providing high speed rail services between HK and Guangzhou and a connection to the national high-speed passenger rail network serving major mainland cities outside the Guangdong province (The Project).

13.2 The Project consists of an underground terminus in West Kowloon and approximately 26 km of tunnels from the terminus to the mainland boundary near Huanggang. After crossing the boundary, the Mainland section of the high-speed railway runs north for a further 116 km to Guangzhou. Trains on the Hong Kong section are intended to operate at speeds up to 200 kph. Construction is scheduled to commence in late 2009 for completion in 2015.

13.3 Referring to Chapter 2 of the EIA, the selection of construction methods has been optimised to minimise, as far as possible, the use of explosives depending on the type of material to be excavated. The breakdown per excavation method is approximately:

· Tunnel Boring Machine (TBM) (specially designed for soft soil excavation): approx. 8.5 km;

· Cut and Cover: approx. 2.0 km; and

· Drill and Blast: approx. 15 km.

13.4 As shown above, a substantial length of the tunnels and adits (approximately 15 km) will be excavated in rock. A significant amount of explosives will be required for the construction of rock caverns, tunnels and adits.

13.5 To enable a timely delivery of explosives to site and in order to meet the proposed construction work programme, two Explosives Storage Magazines (Magazines) are required. These will be located at Tai Lam and So Kwun Wat. The sites were selected considering the distance to the work areas as well as other constraints such as land availability, minimum separation distances from magazine to populated area, etc (ref.1).

13.6 With reference to the EIA Study Brief (ESB-197/2008), there is no work area within the consultation zone of the PHIs under which the alignment is passing through. Based on this, the PHI assessment is not considered applicable for this hazard to life assessment.

13.7 The QRA for the storage and transport of explosives relates to the construction phase of the project, in which blasting activities are expected. There will be no explosives handled during the operational phase.

13.8 The Hazard to Life assessment under this section of the EIA, addresses, in particular, the following:

· Storage of explosives at the proposed magazines (cartridged emulsion, detonating cord and detonators) including handling of explosives within the magazine sites; and

· Transport of Explosives to the delivery points.

13.9 Further details of the QRA for the Project are presented in the Appendix 13.

Legislation requirement and evaluation criteria

13.10 The key legislation and guidelines that are considered relevant to the development of the proposed Express Rail Link project are as follows:

· Dangerous Goods Ordinance, Chapter 295;

· Environmental Impact Assessment Ordinance (EIAO), Chapter 499; and

· The EIA Study Brief (ESB-197/2008), Section 3.4.2.

EIAO Technical Memorandum (EIAO-TM)

13.11 The requirement for a QRA of projects that involve the storage and transport of dangerous goods where a risk to life is a key issue with respect to the Hong Kong Government Risk Guidelines (HKRG) is specified in Section 12 of the Environmental Impact Assessment Ordinance Technical Memorandum (EIAO-TM).

13.12 The relevant authority for a QRA study relating to an explosives magazine storage facility and the transport of the explosives is the Environmental Protection Department (EPD), as specified in Annex 22 of the EIAO-TM.

13.13 Annex 4 of the EIAO-TM specifies the Individual and Societal Risk Guidelines.

Hong Kong Government Risk Guidelines (HKRG), EIAO TM Annex 4

13.14 Individual risk is the predicted increase in the chance of fatality per year to an individual due to a potential hazard. The individual risk guidelines require that the maximum level of individual risk should not exceed 1 in 100,000 per year i.e. 1 x10^-5 per year.

13.15 Societal risk expresses the risks to the whole population. The HKRG is presented graphically in Figure 1. It is expressed in terms of lines plotting the frequency (F) of N or more deaths in the population from incidents at the installation. Two F-N risk lines are used in the HKRG that demark “acceptable” or “unacceptable” societal risks. The intermediate region indicates the acceptability of societal risk is borderline and should be reduced to a level which is “as low as is reasonably practicable” (ALARP). It seeks to ensure that all practicable and cost effective measures that can reduce risk will be considered.

Figure 1 Hong Kong Government Risk Guidelines

Study Objectives and Methodology

13.16 The objective of the QRA study is to assess the risk to life of the general public from the hazards that arise from the storage and transport of the explosives that are required to facilitate the construction of the Project. The results of the QRA should then be compared with the HKRG.

13.17 The detailed requirements of the study are given in Section 3.4.2 of the EIA study brief. The main requirements are:

· To identify hazardous scenarios associated with the storage and transport of explosives and then determine a set of relevant scenarios to be included in the QRA;

· To carry out a QRA to determine risks to the surrounding population in both individual and societal terms;

· To compare the individual and societal risks with the Criteria for Evaluating Hazard to Life stipulated in Annex 4 of the EIAO-TM; and

· To identify and assess practicable and cost effective risk mitigation measures.

13.18 The methodology of the hazard assessment should be consistent with previous studies having similar issues.

13.19 The elements of the QRA are shown schematically in Figure 2. It includes the following:

· Collection and review of relevant data for the proposed Magazines, the transport from the magazines, as well as population and vulnerable receptors, such as slopes, retaining walls etc., in the vicinity of storage, the tunnel construction and proposed transport routes;

· Hazard identification. A review of literature and accident databases was undertaken and updated. These formed the basis for identifying all the hazardous scenarios for the QRA study;

· Frequency estimation. The frequencies, or the likelihood, of the various outcomes that result from the hazards associated with the storage and transport of explosives was taken primarily from the ERM 2008 study (ref.2), which has been accepted by the relevant authorities. Where necessary, to consider specific factors applicable for the Project, recent accident statistics, and to reflect the current knowledge on the explosives’ properties, these frequencies were modified or updated making reference, as far as possible to published references; such as the previous Hong Kong studies , UK HSE, US DoD, Dutch TNO, latest accident statistics from the Transport Department and Fire Service Department, etc.;

· For all identified hazards, the frequency assessment has been documented and the consequences were modelled;

· The consequence model employed in this study is the ESTC model (ref.3), developed by the UK Health and Safety Commission (HSC). Although, there have been a number of recent studies suggesting that the ESTC (2000) models should be reviewed for applicability to explosive stores and transport, these models are still the recommended models in the UK and adopted in the ERM 2008 study (ref.2).

· The frequency model was updated, in accordance with the methodology adopted in the ERM 2008 study and the DNV 1997 study (ref.4) which was based on the ACDS (ref.5) and Moreton 1993 studies (ref.6), to reflect the current Transport Department statistics, Fire Services Department statistics, specific design features applicable for the Project and current knowledge of explosives.

· The consequence and frequency data were subsequently combined using ERM’s in-house proprietary software Riskplot ^TM to produce the required risk estimates. The transport part of the risk assessment has been updated compared to the ERM 2008 study (ref.2). An in-house Explosive Transport GIS Risk Assessment tool (E-TRA) has been developed to account for three-dimensional blast effects on buildings and the effect of accidental explosions on elevated roads. It also accounts for traffic jam scenarios which could occur in some accidental scenarios as reported in ref.4. The model is summarised in Section 3.2 of Appendix 13 and has been validated against Riskplot ^TM.

· Finally, the results from the risk assessment were compared to the EIAO-TM Criteria. Recommendations have been made where required to ensure compliance with EIAO-TM Criteria, relevant best practice, and to reduce the overall risk levels.

Figure 2 Schematic Diagram of QRA Process

13.20 The methodology used in this hazard assessment is consistent with previous studies. However, the methodology has been updated and refined, particularly the frequency of explosives truck accident, following the comments from Mines Division to review and update the accident data based on recent history. Details of the analysis can be found in Appendix 13.

Facility Details

Project Overview

13.21 The Project comprises the following key elements:

· Approximately 26km of underground railway running from the terminus in West Kowloon to the boundary at Huanggang;

· A terminus in West Kowloon, and its associated building elements such as ventilation buildings, ventilation shafts, traction sub-station, and seawater cooling system;

· Seven tunnel ventilation buildings at Mai Po, Ngau Tam Mei, Pat Heung, Shing Mun, Kwai Chung, Nam Cheong and Mong Kok West, and an Emergency Access Point (EAP) at Tai Kong Po;

· Stabling sidings and maintenance facilities located at Shek Kong (Shek Kong Stabling Sidings (SSS)) to provide for stabling, maintenance and cleaning; and

· An emergency rescue station (ERS) located next to the SSS.

13.22 The proposed Project alignment and work areas are shown in Figure 3.

13.23 The Project is scheduled to commence in late 2009 for completion in 2015. Excavation in rock by blasting will be ongoing generally from 2011 to mid 2013 for a significant length of the tunnels and adits (approximately 15 km).

13.24 For the purpose of this study, the alignment is divided into two areas. The northern area contains those tunnels and associated structures for which excavation will be carried out from worksites within the northern New Territories. The southern area contains those tunnels and associated structures for which excavation will be carried out from worksites within the urban Kowloon areas. Each of the northern and southern areas has its own explosives magazine site to limit the travelling distances of explosive trucks from the magazine to the worksites.

13.25 Two categories of explosives will be used for the construction of tunnel by Drill and Blast methods. These are:

· Initiating explosives: cartridged emulsion explosives, detonating cord and detonators; and

· Blasting explosives: site-sensitized bulk emulsion explosives or site-mixed ammonium nitrate – fuel oil (ANFO).

13.26 Cartridged emulsion and detonating cord will be delivered from the explosives magazines to the various construction sites by the appointed contractors using Mines Division licensed trucks. These explosives are classified as an explosive Class 1.1D under United Nation (UN) Classification (ref.7) and as a Category 1 (Explosive and blasting agents) Dangerous Goods under the Hong Kong Dangerous Goods Ordinance.

13.27 Detonators will also be used to initiate the blast at the working face. As used in this project, they are classified as Class 1.4B or 1.4S explosives under the UN classification system and Category 1 (Explosives and Blasting Agents) under the Hong Kong Dangerous Goods Ordinance, and will be transported from magazines to work areas by a dedicated truck, which is identical to, but independent of the truck carrying the emulsion explosives and detonating cord. Detonators approved for use in Hong Kong are of the Non-Electric Type, ie. initiated by shock tube.

13.28 Explosives classified as Class 1.1 is defined as substances and articles which have a mass explosion hazard while Class 1.4 explosives present no significant hazard outside the packaging. To comply with the classification, it is required to ensure that the explosive is safe to transport, to pass a series of classification tests in accordance with the UN test manual, 2003 (ref.8). Due to different properties of explosives, a compatibility class is also assigned, as applicable to this Project. Type “B” is defined as “An article containing a primary explosive substance and not containing two or more protective features” and type “S” is defined as “The substance or article so packed or designed that any hazardous effects arising from accidental functioning are limited to the extent that they do not significantly hinder or prohibit fire fighting or other emergency response efforts in the immediate vicinity of the package”.

13.29 Bulk emulsion precursor will be transported to the blast sites by the appointed third party supplier. It is classified as an oxidising agent Class 5.1 under the UN Classification system and as Category 7, ie. strong supporter of combustion under the Hong Kong Dangerous Goods Ordinance. Prior to sensitizing, it is not considered as an explosive, and hence outside the scope of this QRA. Bulk emulsion will not be stored within the magazine.

13.30 Depending on blasting requirements, ANFO may be used in this project. ANFO is classified as UN HD 1.1D under UN Classification. It consists of an oxidizing substance mixed with 6% by weight of diesel fuel oil. ANFO will be produced at the construction work area by using a mixing truck and hence outside the scope of this QRA.

Statutory/ Licensing Requirements

13.31 The statutory / licensing requirements with respect to the explosives (Cat. 1 Dangerous Goods) or the oxidizing substances (Cat. 7 Dangerous Goods) used to prepare explosives at the construction work area as well as relevant government departments/ authorities’ advice and practice on the proposed transport and storage of explosives for the blasting activities are summarized below.

Category 1 Explosives and Blasting Agents

· Responsible authority: The Commissioner of Mines Division

· Applicable regulations/ guidance notes:

- Supply of detonators and cartridged emulsion explosives (under the Dangerous Goods (General) Regulations Cap. 295B);

- Approved explosives for blasting in Hong Kong (under the Dangerous Goods (General) Regulations Cap. 295B);

- Blast design (under the Dangerous Goods (General) Regulations Cap. 295B);

- Blast loading and execution (under the Dangerous Goods (General) Regulations Cap. 295B);

- Removal of explosives (under Regulation 4 of the Dangerous Goods (General) regulations Cap. 295B);

- Approval of an explosives delivery vehicle (under CEDD’s “Guidance Note on Requirements for Approval of an Explosive Delivery Vehicle” (ref.9));

- Explosive delivery vehicle design features and safety requirements (under CEDD’s “Guidance Note on Requirements for Approval of an Explosive Delivery Vehicle” (ref.9);

- Explosive magazine (under CEDD’s document “How to Apply for a Mode A Explosives Store Licence” (ref.10));

- Explosives produced at site (under Regulation 31A of the Dangerous Goods (General) Regulations Cap. 295B); and

- Explosives load per truck (in accordance with the Removal Permit under the Dangerous Goods (General) Regulations Cap. 295B).

Category 7 Strong Supporters of Combustion

· Responsible authority: Fire Services Department

· Applicable regulations:

- Storage of oxidizing agents (under Dangerous Goods (General) Regulations Cap. 295B)

13.32 This Project will use cartridged emulsion explosives as initiating explosives. For blasting explosives, bulk emulsion or ANFO will be used. Therefore, the storage and transport requirements for explosives are the minimum required quantities for the Project.

Storage Magazine Details

13.33 A magazine site is proposed to be built at Tai Lam (for northern area) and another one at So Kwun Wat (for the southern area). The design, construction and operation of the magazines will comply with the general requirements from the Commissioner of Mines (ref.10).

13.34 Each magazine is designed to store sufficient quantities of explosives for two days so as to allow blasting to be carried out 24 hours per day and provide a buffer in the event of delivery interruption to the magazines by Mines Division.

13.35 The northern magazine at Tai Lam (Tai Lam Magazine) serves three worksites (Contract 824 and Contract 822) in the Northern New Territories. The site comprises two individual magazine stores, each with a single structure storing 400 kg of explosives such as cartridged emulsion, detonating cord and boosters. A storage chamber for detonators holding 1900 detonators, equivalent to two days supply, is provided next to each explosives chamber. The detonators have a very low explosive mass and contain less than 1 gram of high explosives per detonator. Therefore, the net explosive quantity within the detonator chamber is less than 2 kg.

13.36 The southern magazine at So Kwun Wat (So Kwun Wat Magazine) serves four worksites within the urban Kowloon areas (Contract 822 and Contract 821). The site comprises two magazine compounds, with two magazine structures storing 300 kg of explosives each. Similarly, detonator storage chambers holding a total of 2800 detonators, equivalent to two days supply, are provided next to the explosives chamber for each contract.

13.37 The work areas and the associated explosives using contract packaging for the two magazines are shown in Table 13.1.

13.38 Each of the magazine buildings is a single-storey, detached and bunded structure, which is fenced and secured in accordance with the Commissioner of Mines’ requirements. Details of the requirements are defined in the CEDD document “How to Apply for a Mode A Explosives Store Licence” (ref.10). Surface road access suitable for 11-tonne trucks is also provided for delivery of explosives.

Table 13.1 Project Contracts and Work Areas (Blasting only)

Contract No.	Storage Magazine	2 Day Explosive Storage Requirement per contract	Delivery Point (Work Area)
Southern Area
821	So Kwun Wat	600 kg (300 kg each x 2)	2d - Kwai Chung
			2e - Mei Lai Road
822	So Kwun Wat	600 kg (300 kg each x 2)	2b - Shek Yam
			2c - Shing Mun
Northern Area
822	Tai Lam	400 kg	1b - Pat Heung
824	Tai Lam	400 kg	1c - Tai Kong Po
			1d - Ngau Tam Mei

Transport Route Details

13.39 Mines Division will deliver explosives to the Magazines on a daily basis, from where explosives will be transferred to the work areas by the contractors for the daily or twice-daily blasts depending on requirements for construction. Loads will be limited to a maximum of 200 kg per truck or less in accordance with the Removal Permit issued by Mines Division.

13.40 The explosives will be delivered to the various construction work areas using the public roads as shown in Figure 4. The proposed delivery points from the two magazines are shown in Table 13.1.

13.41 According to the current construction programme, delivery of explosives to the seven delivery points will be required from 2011 to 2013. A maximum of 6 will be in operation simultaneously during the 8-month period from March to October 2012 while on average, deliveries to 4 or 5 works sites are expected at any one time during the 3-year construction phase.

13.42 In addition to cartridged emulsion and detonating cord, detonators will also be transported. Detonators will be transported in a separate and dedicated licensed vehicle.

13.43 The licensed explosives delivery vehicles (LGV pick-up trucks) for delivery of explosives from the site magazines to the worksites, used as the basis for this QRA, will have the following safety features:

· Diesel powered;

· Manual fuel isolation switch;

· Forward mounted exhaust with spark arrestor;

· All electrical wiring or electrical devices will be shrouded in fire resisting conduits;

· Fuel tank will be protected from accidental damage, and designed to prevent accumulation of spilt fuel on any part of the vehicle;

· Two fire extinguishers will be mounted on an easily accessible position on the vehicle;

· Fire resistant material will be fitted between the wheel arches and the goods compartment;

· Lockable wood lined steel or aluminium receptacles mounted on the vehicle tray; and

· Fold down / up explosives warning signs and rotating flashing light.

13.44 In addition, a fire screen will be fitted between the cab and the load compartment and between the load compartment and the chassis.

Base Case and Worst Case for Quantitative Risk Assessment

13.45 The actual construction programme will depend on the detailed design and appointed contractors. It may also depend on the actual achievable progress rates which may vary due to specific site conditions (e.g. geology). To consider the uncertainty in the envisaged construction programme, a Base Case, which accounts for expected programme variations, and a Worst Case, which presents the worst programme scenario, have been considered for the assessment.

Base Case Programme for Hazard to Life Assessment

13.46 Based on the envisaged construction programme and sequence of works, the annual travel distance by explosive vehicles, carrying cartridged emulsion and detonating cord, will reach a peak in the period between September 2011 and August 2012, with an annual number of deliveries of 2671 and a travel distance is around 42,000 km. This period is referred as the peak explosive delivery period which is taken to represent the Base Case scenario for the Hazard to Life Assessment. The delivery frequency has been estimated on the basis that, for a given delivery point, each delivery will be made to each blast face independently of the other blast faces even if the load could be transported on the same truck. This approach, although slightly conservative, accounts for expected delivery variations during the peak delivery period, within which, separate deliveries will be generally undertaken.

13.47 The explosive load has been estimated on the basis that, for a particular delivery point, when the blast time for various faces coincides in the construction programme within the peak delivery period, explosives will be transported on the same truck. This applies, for instance, when the blast programme of the northern drives and southern drives for a particular delivery point overlaps.

13.48 In the Base Case, it was considered that blasting could be carried out at predetermined time during the day following the envisaged construction programme. A distribution of delivery time has thus been considered based on the construction programme.

13.49 The Base Case programme is summarized in Table 13.2.

Table 13.2 Summary of Explosives Deliveries and Transport Quantities (for Base Case)

Delivery Point	Explosive Deliveries in Peak Delivery Period (trips/y)	Peak Transport Quantity (kg/trip)
1b - Pat Heung	531	61
1c - Tai Kong Po	341	42
1d - Ngau Tam Mei	157	42
2b - Shek Yam	392	51
2c - Shing Mun	27	27
2d - Kwai Chung	606	78
2e - Mei Lai Road	617	31
Total	2671

Worst Case Programme for Hazard to Life Assessment:

13.50 The Hazard to Life Assessment also covers the Worst Case scenario. It addresses the possibility that, due to construction uncertainties or contractors’ methods of working, the contractors propose an actual construction programme which differs from the envisaged construction programme. Such a case may result in a higher number of delivery trips. Return trips loaded with explosives will generally be avoided, however, due to some construction uncertainties, a number of return trips could be made. Overall, in the worst case, a 20% increase in the number of deliveries compared to the base case scenario may result based on previous project experience.

13.51 In this project, for a particular delivery point, it is possible that the explosive load required for each delivery will be higher than that indicated in the envisaged programme due to particular site conditions and blasting requirements; however, the explosive load to be transported will be, as a worst case, the maximum explosive load for the site (sum of the loads for each blast face within the same work site). The delivery load, in the Worst Case Scenario, has been selected as the sum of the loads for each blast face within the same work site.

13.52 In this Worst Case Scenario, explosives could be delivered at peak day times.

13.53 The Worst Case programme is summarized in
Table 13.3.

Table 13.3 Summary of Explosives Deliveries and Transport Quantities (Worst Case)

Delivery Point	Explosive Deliveries in Worst Case (trips/y)	Transport Quantity (kg/trip)
1b - Pat Heung	637	125
1c - Tai Kong Po	409	42
1d - Ngau Tam Mei	188	42
2b - Shek Yam	470	112
2c - Shing Mun	32	27
2d - Kwai Chung	727	129
2e - Mei Lai Road	740	76
Total	3205

Figure 3 Proposed Alignment and Work Areas

Figure 4 Project Alignment, Proposed Magazine Locations and Explosives Transport Routes

Population Data

13.54 Population within the vicinity of the explosives magazines is estimated based on site surveys and information gathered from Geographic Information System (GIS) database 2007/2008 data (ref.11) and aerial maps. There are no known (current or future) buildings or any other structures in the hazard zone of the proposed Magazines.

13.55 Population data used for the transport risk assessment have been collected by a combination of site survey, Base District Traffic Model (BDTM) 2011, Annual Traffic Census 2007 (ref.12), Road Traffic Accident Statistics 2007 (ref.13&14), Centamap (2008) and GIS tools. For areas where information is not available, assumptions have been used consistently with the previously approved studies. Three types of population have been considered.

· Pedestrian population on footpaths and pavements next to delivery routes;

· Road population; and

· Building population.

13.56 The approach to modelling the risks during transport of explosives is fully 3-dimensional and GIS based. It also accounts for the potential increased risk when explosives truck travel on elevated roads.

13.57 The population data adopted in the QRA is detailed in Appendix 13.

Hazard Identification

13.58 Hazard identification consisted of a review of the following:

· Explosives properties;

· Scenarios presented in previous relevant studies;

· Historical accidents; and

· Discussions with explosives and blasting specialists.

Hazards of Explosives

13.59 Explosives present a hazard to both property and people. This hazard manifests itself in the following ways:

· Blast and pressure wave;

· Flying fragments or missiles;

· Thermal radiation; and

· Ground shock.

13.60 In the case of explosions, the biggest damage is usually caused by the blast effects. The blast and pressure waves can cause injury to sensitive human organs such as the ears and lungs. However, considerable overpressures are required for fatalities to occur, and consequently people need to be fairly close to the scene of the direct explosion effects to be significant.

13.61 Other effects due to the blast or overpressure are associated with damage to buildings and other structures/ objects or the impact of debris and fragments from damaged building structure, and the vehicle or container in which the explosives are held. Moreover, injury may occur when people are displaced or swept away, or due to the violent movement of internal organs within the body.

13.62 An explosion may result in the formation of a short duration fireball since the fuel content of the emulsion is oxidised. However, although it is generally the case that the thermal hazards from an explosives detonation event is of less concern than the blast and fragment hazards.

Review of Incidents

13.63 A review of reported safety incidents involving storage, transport and disposal of explosives (in industrial applications) was carried out. Records were retrieved mainly from the UK Health and Safety Executive (UK HSE)’s Explosives Incidents Database Advisory Service (EIDAS) (ref.15), US Mine Safety and Health Administration (MHSA) (ref.16) and Western Australia’s Department of Consumer and Employment Protection (DOCEP) (ref.17). The records provided are also supplemented with information obtained from various sources. An analysis of accident data is provided in Section 5 and Section 6 of Appendix 13.

Scenarios for Hazard Assessment

13.64 The following table (Table 13.4) provides a summary of the scenarios considered in this QRA.

Table 13.4 Scenarios Considered in the QRA study

Tag	Scenario
Storage of Explosives
01	Detonation of full load of explosives in one store in So Kwun Wat site
02	Detonation of full load of explosives in one store in Tai Lam site
03	Detonation of full load of explosives in one contractor truck on the access road within the So Kwun Wat magazine site boundary
04	Detonation of full load of explosives in one contractor truck on the access road within the Tai Lam magazine site boundary
Transport of Explosives
05	Detonation of full load of explosives in one contractor truck on public roads – from So Kwun Wat site to delivery point 2b Shek Yam
06	Detonation of full load of explosives in one contractor truck on public roads – from So Kwun Wat site to delivery point 2c Shing Mun
07	Detonation of full load of explosives in one contractor truck on public roads – from So Kwun Wat site to delivery point 2d Kwai Chung
08	Detonation of full load of explosives in one contractor truck on public roads – from So Kwun Wat site to delivery point 2e Mei Lai Road
09	Detonation of full load of explosives in one contractor truck on public roads – from Tai Lam site to delivery point 1b Pat Heung
10	Detonation of full load of explosives in one contractor truck on public roads – from Tai Lam site to delivery point 1c Tai Kong Po
11	Detonation of full load of explosives in one contractor truck on public roads – from Tam Lam site to delivery point 1d Ngau Tam Mei

Frequency analysis

13.65 Deflagration or detonation explosion may occur during the transportation of explosives from the magazines to the construction sites. This accidental explosion can be caused by spontaneous fire (non-crash fire), fire after a vehicle crash (crash fire), impact initiation in crash (crash impact) or spontaneous explosion during the normal condition of transport which may occur if the cargo load contains ‘unsafe explosives’.

13.66 In this study, a fault tree has been developed to assess the overall explosion frequency as applicable to the Project contractors’ trucks based on the latest information available on the explosives properties, vehicle incident frequencies provided by the Transport Department and Fire Services Department, and the specific explosive transport vehicle design and operation to be used as part of the Project. The details of the frequency assessment are provided in Section 6 of Appendix 13.

Frequency analysis for Transport of Explosives

13.67 Based on Hong Kong vehicle accident data, the frequencies of explosives initiation during road transport are estimated as 7.69 x 10^-10/km for the truck on non-expressway and 6.87 x 10^-10/km on expressway, using a fault tree approach. The fault tree model has considered the frequencies of non-crash fire, crash fire, crash impact and unsafe explosive. Adjustment factors were applied to the model to account for the probabilities of explosive initiation due to thermal stimulus or crash impact.

Frequency analysis for Storage of Explosives

13.68 The overall initiating event frequency within the storage magazine is based upon the UK HSE recommended value of 1 x 10^-4 per storehouse year. Additional risk due to manual transfer of explosives, lightning strike, aircraft crash, hill/ vegetation fire, earthquake and other site specific considerations to XRL project were also considered but their contribution was negligible. (see Section 6 of Appendix 13).

Consequence analysis

13.69 The probability of fatality due to blast over-pressure, have been estimated using the method detailed by the UK HSE Explosives Storage and Transport Committee (ref.3) The fatality contours are calculated at 90%, 50%, 10%, 3% and 1% fatality. Details of the model and the results are given in Section 7 of Appendix 13.

13.70 Special features such as slopes and service reservoirs along the transport routes or near the magazine sites were identified with respect to the potential secondary hazards. These aspects of risk were evaluated separately, and were found either insignificant or already covered by applying the blast overpressure-fatality model (ie. ESTC model (ref.3)).

Risk Summation

Individual Risk Results

13.71 The individual risk (IR) contours associated with the Project are shown in Figure 5, Figure 6, Figure 7 and Figure 8. In Figure 7 and Figure 8, the ‘indoor’ refers to the population located inside buildings, and the ‘outdoor’ refers to the population located outside buildings ie in open area. At the same distance from a potential explosion, persons located inside buildings are more vulnerable to explosion than persons located outside buildings as they are exposed to more hazards such as debris from broken windows, etc. This explains a higher individual risk for indoor population.

13.72 For the delivery routes, the IR data represent the highest individual risk, occurring on the road in the same lane as the explosives delivery truck. It is observed that the maximum IR is about 4.6´10^-8 per year. This is a low risk when compared to Hong Kong Risk Guidelines which require the offsite IR from a fixed installation to be below 10^-5 per year.

13.73 Both storage magazines are in remote areas. The individual risk contours of 1 x 10^-5 per year extend outside the site boundary. However this impacts only on woodland areas where there is no continuous presence of people. Assuming occupancy factor by members of the public for about 2 hours per week (during the weekend or weekdays people may be in the vicinity hiking) this would translate to a presence factor of 0.01. The IR for specific individuals offsite would therefore be about two orders of magnitude less than that indicated by the IR contours, and clearly less than 10^-5 per year for all the off-site areas. Hence it can be concluded that individual risk is acceptable.

Figure 5 Maximum IR for Northern Delivery Routes (from Tai Lam Magazine)

Figure 6 Maximum IR for Southern Delivery Routes (from So Kwun Wat Magazine)

Figure 7 IR of Proposed Tai Lam Magazine

Indoor Outdoor

Figure 8 IR of Proposed So Kwun Wat Magazine

Indoor Outdoor

Societal Risk Results

13.74 The societal risk results for explosives storage and transport have been combined to produce the overall societal risk results for the base case and the worst case (Figure 9). These include the two magazine sites at Tai Lam and So Kwun Wat and the associated transport routes to the 7 work sites.

13.75 The Base Case represents the risks associated with the envisaged blasting programme. It can be seen that the risks lie in the upper ALARP region.

13.76 The Worst Case represents the maximum risks associated with the worst blasting scenario. The risks, as expected, are higher than the base case but still within the ALARP region.

13.77 Figure 10 shows the F-N curve for the Base Case with a breakdown by storage and transport. It is observed that risks from the magazines are negligible compared to the transport risks since the two magazines are located in remote areas with very low population density nearby.

13.78 The F-N curves for both base case and worst case are within the As Low as Reasonably Practicable (ALARP) Region as per HK EIAO-TM. Therefore, mitigation measures need to be considered to reduce the risk. The ALARP assessment is provided in Section 9 of Appendix 13.

13.79 The potential Loss of Life (PLL) for the base case and the worst case are given in Table 13.5 and Table 13.6 respectively. The PLL for this project has been evaluated at 3.45 x 10^-4 per year. The maximum PLL value for the Project is estimated at 1.27 x 10^-3 per year, which is obtained from the worst case.

Figure 9 F-N Curves for Storage and Transport of Explosives

Figure 10 F-N Curve for Base Case with Breakdown by Transport and Storage

Table 13.5 Potential Loss of Life for Base Case

Base Case	PLL (per year)	Percentage Contribution (%)
Storage of Explosives
Tai Lam Magazine	7.99E-09	0.002%
So Kwun Wat magazine	7.99E-09	0.002%
Transport of Explosives
Tai Lam Magazine to Pat Heung	5.24E-05	15.21%
Tai Lam Magazine to Tai Kong Po	1.81E-05	5.26%
Tai Lam Magazine to Ngau Tam Mei	9.49E-06	2.75%
So Kwun Wat Magazine to Shek Yam	6.45E-05	18.72%
So Kwun Wat Magazine to Shing Mun	2.94E-06	0.85%
So Kwun Wat Magazine to Kwai Chung	1.14E-04	32.98%
So Kwun Wat Magazine to Mei Lai Road	8.35E-05	24.23%
Total	3.45E-04	100.00%

Table 13.6 Potential Loss of Life for Worst Case

Worst Case	PLL (per year)	Percentage Contribution (%)
Storage of Explosives
Tai Lam Magazine	7.99E-09	0.001%
So Kwun Wat magazine	7.99E-09	0.001%
Transport of Explosives
Tai Lam Magazine to Pat Heung	1.88E-04	14.87%
Tai Lam Magazine to Tai Kong Po	4.81E-05	3.80%
Tai Lam Magazine to Ngau Tam Mei	2.48E-05	1.96%
So Kwun Wat Magazine to Shek Yam	2.57E-04	20.26%
So Kwun Wat Magazine to Shing Mun	7.33E-06	0.58%
So Kwun Wat Magazine to Kwai Chung	4.08E-04	32.24%
So Kwun Wat Magazine to Mei Lai Road	3.33E-04	26.29%
Total	1.27E-03	100.00%

ALARP Assessment

13.80 Since the risks posed by the project, for both cases considered, are within the ALARP region specified in EIAO-TM Annex 4, this implies that risk reduction measures and / or alternate options should be explored for the Project.

13.81 It was found that the risks arising from explosives transport are much more significant than that of explosives storage; hence the ALARP assessment focuses on the transportation aspects of explosives.

13.82 Where the risk falls into the ALARP region, the risks associated with each probable hazardous event should be reduced to a level ‘as low as reasonably practicable’. This firstly requires the identification of any ‘practicable’ options regardless of their cost. A mitigation option is considered ‘practicable’ if an engineering solution exists and can be implemented on the XRL project regardless of the cost without affecting the project construction programme. Secondly, the extent to which the risk should be reduced is usually measured as a trade off between the risk reduction, ie the safety benefits and the cost of the risk reduction measure. A mitigation option is considered ‘reasonable’ if the cost of implementing the option is not grossly disproportionate to the achieved safety benefits.

13.83 Risk mitigation measures may take the form of engineered measures, controls in the zones most impacted by the hazardous scenarios presented by this project, or operation and procedural controls.

Approach to ALARP Assessment

13.84 The approach consists of identifying potential justifiable mitigation measures, assessing their practicability for this project and evaluating their cost and comparing with the safety benefits of implementing the measures. Combinations of mitigation measures are also considered.

13.85 The safety benefits are evaluated as follows:

Safety Benefits = Value of Preventing a Fatality x Aversion Factor x Reduction in PLL value

x Design life of mitigation measure

13.86 The Value of Preventing a Fatality (VPF) reflects the tolerability of risk by the society and therefore the monetary value that the society is ready to invest to prevent a fatality. For the purpose of this assessment and for consistency with previous studies, the Value of Preventing a Fatality is taken as HK$33M per person, which is the same figure as used in previous Hazard Assessment studies (derived from ref.5 but updated to current prices.

13.87 Depending on the level of risk, the value of preventing a fatality may be adjusted to reflect people’s aversion to high risks or scenarios with potential for multiple fatalities. The methodology for application of the ‘aversion factor’ follows that developed by EPD (ref.18), in which the aversion factor is calculated on a sliding scale from 1 (risks at the lower boundary of the ALARP region of the Risk Guidelines) up to a maximum of 20 (risks at the upper boundary of the ALARP region). The adjusted VPF using the aversion factor of 20 is HK$660M. This value is a measure of how much the society is willing to invest to prevent a fatality, where there is potential for an event to cause multiple fatalities.

13.88 The maximum justifiable expenditure for this Project is calculated as HK$ 2.51M assuming the design life of mitigation measure is 3 years based on the construction phase of the XRL project during which storage and transport of explosives will be involved, with the PLL of 1.27 x 10^-3 per year, which is obtained from the Worst Case.

13.89 For an ‘achievable’ mitigation measure to be potentially justifiable, its cost should be less than the Maximum Justifiable Expenditure.

Potential Justifiable Mitigation Measures

13.90 The potential options that have been examined in the ALARP assessment include the following categories.

· Options eliminating the need for a Magazine or eliminating the risk (eg. Use of alternative methods of construction (‘hard rock’ TBMs));

· Options reducing significantly the quantities of explosives to be used such as use of ‘hard rock’ TBM or alternatives to cartridged emulsion;

· Options reducing significantly the distance run by contractors’ explosive trucks such as closer magazine sites and alternative routes. The magazine and route options considered are summarised below:

- The alternative magazine sites to So Kwun Wat for the southern area and Tai Lam for the northern area considered are: Helicopter site at Lam Kam Road, Pat Heung, Firing Range at Golden Hill, Ying Wa Street, CLP OHL Training School, Kau Wa Keng, Gin Drinkers’ Bay, Kowloon Reservoir, Route Twisk, CAS Yuen Tun Camp and Lo Wai.

With the exception of the Lam Kam Road site, all the alternative candidate sites meeting the Commissioner of Mines’ external separation requirements require an additional cost, due to site constraints, significantly greater than the maximum justifiable expenditure for risk mitigation of HK$ 2.51M (refer to the detailed ALARP assessment in Appendix 13 Table 9.2). Therefore, the alternative magazine site at Lam Kam Road has been selected for further cost-benefit evaluation;

- Based on the review of the possible transport routes for this project, Castle Peak Road has been presented as an alternative route for explosive deliveries from the So Kwun Wat magazine site to the southern work areas. This route option has been selected for further cost-benefit evaluation;

· Options reducing significantly the number of trips to be carried out by contractors’ explosive trucks;

· Options considering improved explosive truck design; and

· Options considering better risk management systems and procedures.

13.91 In summary, the following options have been considered for cost-benefit analysis.

· Option 1: Alternative Magazine Site in Lam Kam, closer to the tunnel alignment

· Option 2: Alternative Route – Castle Peak Road

13.92 The PLL for Option 1 and Option 2 is compared to the PLL for the Worst Case in Table 13.7. This was used as the basis for the cost-benefit analysis/ ALARP assessment presented in Table 13.8

13.93 Other options considered practicable have been either recommended for implementation or assessed comparing the implementation cost with the maximum justifiable expenditure. The evaluation for each option is shown in Table 13.8. More details are available in Section 9 of Appendix 13.

Case	PLL (per year)
Worst Case	1.27 x 10^-3
Option 1: Alternative Magazine Site in Lam Kam	1.08 x 10^-3
Option 2: Alternative Route – Castle Peak Road	1.27 x 10^-3

Table 13.7 Potential Loss of Life for Worst Case, Option 1 and Option 2

Table 13.8 ALARP Assessment Results

Option Description	Practicability	Implementation Cost	Safety Benefits or Justifiable Expenditure	ALARP Assessment Result
Use of alternative methods of construction (TBMs)	Not Practicable	> HK$ 100M	HK$ 2.51M	Not Justified
Use of Magazines Closer to the Construction Sites (Lam Kam Road) (Option Case 1)	Practicable	> HK$ 1M	HK$ 380k	Not Justified
Use of Alternative Route (Castle Peak Road) (Option Case 2)	Practicable	< HK$ 10k	Negative	Tuen Mun Highway is the preferred option
Use of different explosive types (different types of detonating cord)	Pose some limitations	HK$ 1M	No safety benefit	Not Justified
Use of smaller quantities of explosives	Not Practicable	HK$ 6M	HK$ 2. 51M	Not Justified
Safer explosive truck (reduced fire load)	Practicable	-	-	Based on low implementation costs, this option has been directly incorporated in recommendations
Lower Frequency of Explosive Transport	Not Practicable			Option considered but ruled out as not practicable. Not Justified
Reduction of Accident Involvement Frequency (training programme etc.)	Practicable	-	-	Based on low implementation costs, this option has been directly incorporated in recommendations
Reduction of Fire Involvement Frequency (better emergency response, extinguisher types etc.)	Practicable	-	-	Based on low implementation costs, this option has been directly incorporated in recommendations

Conclusions

13.94 A QRA has been carried out to assess the hazard to life issues arising from the storage and transport of explosives during construction of the XRL Project.

13.95 The criterion of Annex 4 of the EIAO-TM for Individual Risk is met. The assessment results show that the societal risk lies within the ALARP region when compared to the criteria stipulated in the EIAO-TM. A detailed ALARP assessment has been undertaken considering a wide range of mitigation measures and the results show compliance with the ALARP principles provided that the following recommendations are followed.

Recommendations

13.96 Following the ALARP principles, the following recommendations are justified and should be implemented to meet the EIAO-TM requirements:

· The truck design should be improved to reduce the amount of combustibles in the cabin. The fuel carried in the fuel tank should also be minimised to reduce the duration of any fire;

· The explosive truck accident frequency should be minimized by implementing a dedicated training programme for both the driver and his attendants, including regular briefing sessions, implementation of a defensive driving attitude. In addition, drivers should be selected based on good safety record, and medical checks;

· The contractor should as far as practicable combine the explosive deliveries for a given work area;

· Only the required quantity of explosives for a particular blast should be transported to avoid the return of unused explosives to the magazines.

· Whenever practicable, a minimum headway between two consecutive truck convoys of 10 min is recommended; and

· The explosive truck fire involvement frequency should be minimized by implementing a better emergency response and training to make sure the adequate fire extinguishers are used and attempt is made to evacuate the area of the incident or securing the explosive load if possible. All explosive vehicles should also be equipped with bigger capacity AFFF-type extinguishers.

General Recommendations

13.97 Blasting activities including storage and transport of explosives should be supervised and audited by competent site staff to ensure strict compliance with the blasting permit conditions. The following general recommendation should also be considered for the storage and transport of explosives:

· The security plan should address different alert security level to reduce opportunity for arson / deliberate initiation of explosives. The corresponding security procedure should be implemented with respect to prevailing security alert status announced by the Government.

· Emergency plan (ie magazine operational manual) shall be developed to address uncontrolled fire in magazine area and transport. The case of fire near an explosive carrying truck in jammed traffic should also be covered. Drill of the emergency plan should be carried out at regular intervals.

· Adverse weather working guideline should be developed to clearly define procedure for transport explosives during thunderstorm.

Storage of Explosives in Magazine Store

13.98 The magazine should be designed, operated and maintained in accordance with Mines Division guidelines and appropriate industry best practice. In addition, the following recommendations should be implemented:

· A suitable work control system should be introduced, such as an operational manual including Permit-to-Work system, to ensure that work activities undertaken during the operation of the magazine are properly controlled.

· There should be good house-keeping within the magazine to ensure that combustible materials are not allowed to accumulate.

· The magazine shall be without open drains, traps, pits or pockets into which any molten ammonium nitrate could flow and be confined in the event of a fire.

· The magazine building shall be regularly checked for water seepage through the roof, walls or floor.

· Caked explosives shall be disposed of in an appropriate manner.

· Delivery vehicles shall not be permitted to remain within the secured fenced off magazine store area.

· Good housekeeping outside the magazine stores to be followed to ensure combustibles (including vegetation) are removed.

· A speed limit within the magazine area should be enforced to reduce the risk of a vehicle impact or incident within the magazine area.

Transport of Explosives

General Recommendations:

13.99 The following measures should be considered for safe transport of explosives:

· Detonators shall not be transported in the same vehicle with other Class 1 explosives. Separation of vehicles should be maintained during the whole trip.

· Location for stopping and unloading from truck to be provided as close as possible to shaft, free from dropped loads, hot work, etc. during time of unloading.

· Develop procedure to ensure that parking space on the site is available for the explosive truck. Confirmation of parking space should be communicated to truck drivers before delivery. If parking space on site cannot be secure, delivery should not commence.

· During transport of the explosives within the tunnel, hot work or other activities should not be permitted in the vicinity of the explosives offloading or charging activities.

· Ensure lining is provided within the transportation box on the vehicle and in good condition before transportation.

· Ensure that packaging of detonators remains intact until handed over at blasting site.

· Emergency plan to include activation of fuel and battery isolation switches on vehicle when fire breaks out to prevent fire spreading and reducing likelihood of prolonged fire leading to explosion.

· Use only experienced driver(s) with good safety record.

· Ensure that cartridged emulsion packages are damage free before every trip.

· Contractors Licensed Vehicle Recommended Safety Requirements:

· Battery isolation switch;

· Front mounted exhaust with spark arrestor;

· Fuel level should be kept as far as possible to the minimum level required for the transport of explosives;

· Minimum 1 x 9 kg water based AFFF fire extinguisher to be provided;

· Minimum 1 x 9 kg dry chemical powder fire extinguisher to be provided;

· Horizontal fire screen on cargo deck and vertical fire screen mounted at least 150mm behind the drivers cab and 100mm from the steel cargo compartment, the vertical screen shall protrude 150mm in excess of all three ( 3 ) sides of the steel cargo compartment;

· Cigarette lighter removed;

· Two ( 2 ) battery powered torches for night deliveries;

· Vehicles shall be brand new, dedicated explosive transport vehicles and should be maintained in good operating condition;

· Daily checks on tyres and vehicle integrity;

· Regular monthly vehicle inspections;

- Fuel system

- Exhaust system

- Brakes

- Electrics

- Battery

- Cooling system

- Engine oil leaks

· Vehicle log book in which monthly inspections and maintenance requirements are recorded; and

· Mobile telephone equipped.

Recommended Requirements for the Driver of the Explosive Vehicles:

13.100 The driver shall:

· be registered by the Commissioner of Mines and must be over the age of 25 years with proven accident free records and more than 7 year driving experience without suspension.

· hold a Driving License for the class of vehicle for at least one ( 1 ) year;

· adopt a safe driving practice including having attended a defensive driving course;

· pass a medical check and is assessed as fit to drive explosives vehicles;

· not be dependent on banned substances;

13.101 Some of the following requirements may also apply to the vehicle attendant(s).

· The driver is required to attend relevant training courses recognized by the Commissioner of Mines. The training courses should include the following major subjects, but not limited to:

- the laws and Regulations relating to the transport of explosives;

- security and safe handling during the transport of explosives;

· Attend training courses provided by the explosives manufacturer or distributor, covering the following:

- explosives identification;

- explosion hazards; and

- explosives sensitivity;

- the dangers which could be caused by the types of explosives;

- the packaging, labelling and characteristics of the types of explosives;

- the use of fire extinguishers and fire fighting procedures; and

- emergency response procedures in case of accidents.

13.102 The driver should additionally be responsible for the following:

· The driver shall have a full set of Material Safety Data Sheets ( MSDS ) for each individual explosive aboard the vehicle for the particular journey;

· The MSDS and Removal Permit ( where applicable ) shall be produced to any officer of the Mines Division of CEDD upon request;

· A card detailing emergency procedures shall be kept on board and displayed in a prominent place on the drivers door;

· Before leaving the magazine the driver together with and/or assisted by the shotfirer shall check the following:

· Packaging integrity and labelling;

· Check that the types and quantities of explosives loaded onto the vehicle are as stipulated in the Removal Permit(s);

· Check that the explosive load does not exceed the quantities stated in the removal permit;

· Check the condition and integrity of the cargo compartment or box;

· Check that detonators are not loaded in the explosives cargo compartment and vice versa;

· Check that the cargo is secured and cannot be damaged during the delivery;

· Ensure that the appropriate placards and a red flag are displayed before leaving the magazine;

· Be competent to operate all equipment onboard the vehicle including fire extinguishers and the vehicle emergency cut-off switches;

· Prohibit smoking when the vehicle is loaded with explosives;

· When explosives are loaded, ensure the vehicle is not left unattended;

· Be conversant with emergency response procedures.

Specific Recommended Requirements for the Explosive Vehicle Attendants:

13.103 When the vehicle is loaded with explosives, it shall be attended by the driver and at least one (1) other person authorized by the Commissioner of Mines. The vehicle attendant shall:

· Be the assistant to the driver in normal working conditions and in case of any emergency

· Be conversant with the emergency response procedures

· Be competent to use the fire extinguishers and the vehicle emergency cut-off switches

· One of the vehicle attendant(s) should be equipped with mobile phones and the relevant MSDS and emergency response plan.

Type of Explosives & their Disposal

13.104 For explosive selection, the following should be considered

· Cartridged Emulsions with perchlorate formulation should be avoided;

· Cartridged Emulsions with high water content should be preferred.

13.105 If disposal is required for small quantities, disposal should be made in a controlled and safe manner by a Registered Shotfirer.

References

1. MTRC, Consultancy Agreement No. NEX-2102, Express Rail Link – Preliminary Design for XRL Tunnels & Associated Structures, “Working Paper No. 13A – Explosives Magazine Site Selection“, 2008. (MTRC 5)

2. ERM, West Island Line: Hazard to Life Assessment for the Transport Storage and Use of Explosives, 2008 (EIA153/2008) (ERM, 2008)

3. HSC, Selection and Use of Explosion Effects and Consequence Models for Explosives, Advisory Committee on Dangerous Substances, 2000 (ESTC, 2000)

4. DNV, The Risk Assessment of the Transport of Explosives in Hong Kong QRA Report, Environmental Protection Department Hong Kong Government, 1997, EPD CE63/94 (DNV, 1997)

5. ACDS, Risk from Handling Explosives in Ports, HSC Advisory Committee on Dangerous Substances, HMSO, UK, 1995 (ACDS, 1995)

6. P A Moreton, An Investigation of the Relative Risks from the Road Transport of Blasting Explosives in Maximum Size Loads of 5te and 16te, February 1993, SRD/HSE R596 (Moreton, 1993)

7. United Nations, Recommendations on the Transport of Dangerous Goods – Manual of Tests and Criteria, 4th Revised Edition, 2003 (TDG-Test Manual, 2003)

8. United Nations, Recommendations on the Transport of Dangerous Goods – Model Regulations, 15th Revised Edition, 2007 (TDG-Model Regulation, 2007)

9. CEDD, Guidance Note on Requirements for Approval of an Explosives Delivery Vehicle, http://www.cedd.gov.hk/eng/services/mines_quarries/doc/gn_03_edv.pdf (CEDD 2)

10. CEDD, How to apply for a Mode A Explosives Store Licence, http://www.cedd.gov.hk/eng/services/mines_quarries/doc/mode_a_store.pdf (CEDD 3)

11. Lands Department, Geographic Information System (GIS) database, http://www.landsd.gov.hk/mapping/en/digital_map/mapprod.htm The latest information on the GIS map of buildings from the Lands Department used in this study comes from 2007/2008 (LD, 2008)

12. Transport Department, Annual Traffic Census 2007 (ATC, 2007)

13. Transport Department, "Road Traffic Accident Statistics”, Government of Hong Kong S.A.R, 2007 (and previous years) (TD, 2007a)

14. Transport Department, Road Traffic Accidents at Junction by Junction Type, Junction Control and Severity 2007, http://www.td.gov.hk/FileManager/EN/Content_1943/07fig2.12e.pdf (TD, 2007b)

15. UK Health and Safety Executive (UK HSE)’s Explosives Incidents Database Advisory Service (EIDAS)

16. Incident database retrieved from US Mine Safety and Health Administration (MHSA)

17. DOCEP, Incident Log Reports retrieved from http://www.docep.wa.gov.au/resourcesSafety/Content/Dangerous_Goods/Incident_log_reports/index.htm (DOCEP)

18. EPD, Technical Note: Cost Benefit Analysis in Hazard Assessment, Environmental Protection Department, Rev. January 1996. (EPD, 1996)