A man has been arrested on suspicion of being in possession of a noxious substance after mustard gas canisters were found in Lincolnshire.
Two people needed treatment in hospital for minor burns and respiratory problems after finding the canisters.
Bomb disposal teams were called to Roughton Moor Woods near Woodhall Spa on Sunday following the find.
The 38-year-old man from Lincoln was arrested on Tuesday night and is in police custody.
Lincolnshire Police said the devices were discovered by people digging for bottles in the woods.
The area was the former RAF Woodhall Spa base from 1942 until it was closed in the mid 1960s.
It is “believed the canisters have been in situ since when the site was an operational RAF base”, the police force said.
Work to confirm the woodland is safe and not a risk to people who visit the area continues, the force added.
Neither victim was seriously injured and they were both discharged from hospital on Sunday.
The canisters were taken to the Defence Science and Technology Laboratory at Porton Down, in Wiltshire.
Mustard gas was used during World War One. It was outlawed by the Geneva Protocol of 1925.
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