How to Handle Corrugated Asbestos Cement Sheets

What are corrugated asbestos cement sheets? Are they harmful to the environment and public health?

Corrugated asbestos cement sheets (CACS) is one of the most common low-risk asbestos containing materials (ACMs).  The asbestos fibres in CACS bind tightly to the base material matrix of the cement.  Therefore, under normal circumstances, CACS will not release any asbestos fibres, cause air pollution or affect public health.  However, improper handling or removal of CACS may give rise to release of very fine asbestos fibres which will remain airborne for a very long period of time.  Under these circumstances, it is possible that people will inhale some of these fibres which, once inhaled, can remain in the body for many years and hence increase their health risk due to such exposure.

Where can CACS be found?

Before the mid-1980s, the roofs of old style village houses were commonly made of CACS and some farmers used CACS for the purposes of blocking soil, catching water for irrigation or preventing flood.  As it is difficult for the general public to tell whether a material contains asbestos or not solely by its appearance or colour, for safety’s sake, you should take a precautionary attitude and treat all suspected materials as ACMs unless proved otherwise by a registered asbestos consultant.

How should I handle CACS used for different purposes?

CACS commonly seen in rural areas can be broadly classified into three types.  The Environmental Protection Department (EPD) recommends the following approaches to handling them:

(1) CACS roofing – The landowner or occupier should comply with statutory requirements by hiring a registered asbestos contractor to handle and dispose of the CACS when the roofing undergoes maintenance or reconstruction.

(2) CACS used for the purposes of blocking soil, catching water for irrigation or preventing flood – Although CACS does not release asbestos fibres under normal circumstances, the landowner or occupier should consider replacing CACS with other materials, and hire a registered asbestos contractor to handle and dispose of the CACS.  Please note that improper handling, cutting, crushing or dismantling of CACS can lead to release of asbestos fibres, cause air pollution or affect public health.

(3) CACS remains intact – Provided that no asbestos removal works are involved and the CACS remains intact, the landowner or occupier can hire a licenced chemical waste collector to collect and dispose of the CACS.  If the CACS is substantially worn, the landowner or occupier must hire a registered asbestos contractor to properly handle and dispose of CACS in accordance with the relevant ordinances.

As registered asbestos contractors will adopt adequate precautionary measures to prevent release of asbestos fibres when removing CACS, the risks involved will be minimal. These measures include segregation of work areas, provision of decontamination facilities, minimum breakage and sufficient wetting during the asbestos removal works. The registered asbestos contractors will also take other safety and health measures such as continuous supervision of the work by a registered asbestos supervisor, providing protective clothing and respiratory protective equipment for workers’ safety as well as air monitoring around the work area. For removal of CACS covered with a layer of concrete screeding, the workers will, under the supervision of the registered asbestos supervisor, separate the CACS carefully into manageable sizes for easy packaging and disposal.

CACS generally does not pose any health risk.  However, when it is broken into pieces or dismantled inappropriately, asbestos fibres will be released and may lead to health problems if inhaled.

As the landowner/occupier, you must hire a registered asbestos contractor to remove, alter or handle the CACS and give a written notice to EPD not less than 28 days prior to the commencement of the works. You may approach EPD for details.

Registered asbestos contractors will place the CACS to be disposed of into metal drums or strong plastic bags for temporary storage in a safe designated place, and arrange for early removal of waste by licensed chemical waste collectors. Please note that asbestos waste is a kind of chemical waste under the Waste Disposal (Chemical Waste) (General) Regulation. It should not be mixed with household waste, nor delivered to refuse collection points or public dumping areas for disposal.