§ Ms Atherton
To ask the Secretary of State for Defence what evidence his Department has(a) collated and (b) evaluated regarding the burning of mustard gas at military establishments and its effect upon neighbouring civilian populations. 
§ Dr. Moonie
Following the decision by the United Kingdom to abandon its offensive chemical weapons capability in 1956 there was a requirement to dispose of the stockpile of the chemical blister agent mustard which had been built up at the time of World War II.
In accordance with the practice of the day these stockpiles were burnt in either open pits or incinerators. No evaluations were made at the time of the effects on neighbouring civilian populations. However, the RAF has conducted extensive research into its historical disposal of chemical weapons.
Today any historical chemical weapons which are recovered are taken to CBD Porton Down for safe disposal. Part of the disposal process of any of these weapons which contain mustard includes incineration. This is undertaken in an on-site incinerator which meets all the standards set by the Environment Agency.