Asbestos in recycled aggregates

A couple of times recently I’ve been asked what to do if you find fragments of cement-bound fibrous materials you suspect to be AC sheeting in recycled aggregates bought for use as hardcore on construction projects. My advice is always to test / reject it if you can before offloading (and preferably while it’s still on the supplier’s premises!), but otherwise to quarantine it on site until it has been properly tested.

WM2 coverThe key question is whether or not the material contains significant quantities of asbestos, as if it does, it is hazardous waste and is unsuitable to be used on site under a U1 waste exemption. (Disposal of it anywhere other than at an appropriately licensed Hazardous Waste disposal site is an illegal activity.) Guidance on the assessment of this in the UK can be found in Appendix A Example 17 (page A59) of the Environment Agencies’ Technical Guidance WM2 “Hazardous Waste. Interpretation of the definition and classification of hazardous waste” (3rd Ed, 2013) which sets down two tests:

  • If the material contains fibres that are free and dispersed, the material will be hazardous waste if as a whole it contains more than 0.1% asbestos.
  • If it is suspected there are pieces of asbestos containing materials (ACM) in the hardcore, the pieces themselves must also be tested, and again the whole of the load is considered to be hazardous waste if any fragment contains more than 0.1% asbestos. Guidance on the minimum size of fragment that must be assessed is given as “any particle of a size that can be assessed as potentially being asbestos by a competent person if examined by the naked eye”. So, close rather than superficial inspection is a must when considering this test.

If the material fails either of these tests it is Hazardous Waste rather than “recycled aggregates” and should be rejected before delivery or otherwise returned to the supplier. It’s always advisable to go and look at recycled hardcore beforehand if you can, and if you spot anything suspicious, ask for it to be tested before delivery. A good quality assurance scheme, such as purchasing from a company that supplies aggregates certified to the WRAP AggRegain Aggregates Protocol should go a long way to avoiding having to deal with these issues on site.

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