So we've been operating in a cave, which was previously backfilled and has now been opened. One particular area of the cave, on one specific rock, the diggers started to get this reaction when using the jackhammer. This also includes swelling of the face, and it's causing open soars on the arms, and it's very itchy. Given the nature and history of this site, this could well be a deterrent left behind.
Some other signs found include this 100+ y/o british plate. and human remains which were reburied. but we only found what looked like a collar bone and wrist or ankle bone.
Looking forward to any ideas.