Published in August 2013

Landfill gas is defined as gas generated from licensed, unlicensed, operating or non-operating landfill sites. It includes gas generated by biodegradation of the deposited waste, and that produced purely by volatilisation.

Degradation of organic matter can give rise to both methane and carbon dioxide, and to a variety of other gases, depending on the ground conditions and the nature of the material. Gases can also be transported in solution by migrating landfill leachate and groundwater.

Within the Geotechnical and Geoenvironmental Industry we may be required to undertake intrusive investigation and install monitoring wells within operational and former landfills and on land near to landfills as well as monitoring and sampling of gas in the ground from monitoring installations and/or landfill gas extraction pipework. Before designing an investigation, a desk study should be completed to allow hazards to be identified associated with waste type, age etc.

This guidance provides a list of the principle hazards associated with gases from landfill sites, advice on emergency procedures and safe working.