Woodhall Spa mustard gas clean-up operation 'cost £289,000'
A major clean-up operation after 150 mustard gas canisters were found in woodland cost more than £289,000, the Ministry of Defence has told the BBC.
Porton Down specialists were brought in after the discovery near Woodhall Spa in Lincolnshire, in October 2017.
A Freedom of Information (FOI) request also revealed contaminated soil and a further six canisters of gas were found by military experts.
Work to make the site safe took place between 1 October and 13 October 2017.
Police declared a "major incident" after the canisters were first discovered on the former World War Two military base at Roughton Woods.
The Ministry of Defence said "the area was then subject to an instrumental search and a soil sampling regime".
"Six canisters were found and taken to DSTL (Defence Science and Technology Laboratory) at Porton Down for subsequent incineration," it said.
Three people have appeared in court charged with a number of offences.
Martyn Tasker, Michaela Tasker and Stuart Holmes appeared before Lincoln magistrates last month charged with possession of mustard gas canisters and discharging mustard gas into fresh inland waters.
All were bailed until 12 September when they are due at the city's crown court.
Two people were treated in hospital for minor burns and respiratory problems when they unearthed the canisters while digging for vintage bottles in the woods.
Mustard gas was used as a weapon during World War One and outlawed by the Geneva Protocol of 1925.
The military shut down RAF Woodhall Spa, which had been a satellite of the main RAF Coningsby site, in the mid-1960s.