Cleaning out old rat poison (pre-1990, UK)
We're having work done on the house and have found piles of white powder along with an old rat nest under the floorboards on top of an old lath and plaster ceiling - it's been there since the previous owner rewired in the 1970s/80s. Google suggests it could be strychnine or other nasty now-illegal poison. It advised us not to brush it up or risk breathing it.
Our electricians need to access the space where the contamination is but we've had to halt work. The room is currently shut up and we're struggling to find someone to remove it. We've rung a few businesses but some don't have equipment to deal with it. Rentokil said no, based on access. It requires a H-class vac which we could hire, except we don't know how to clean it properly afterwards. Also our local council refuses to accept this kind of hazardous waste.
I'm wondering about buying a H-class vac to deal with it myself, but I have no idea how to do this safely and how to ensure that our tradesmen are not at risk. Can anyone who has used, or dealt with, this kind of thing please advise me? Thank you.