Ref your article on the use of formalin in scottish fish farms - here in Norway Formalin is used in large amounts in the seaweed trawling industry - in fact some 800,000 liters per year and it is all dumped into the sea. Ref article from Nrk Norwegian broadcasting https://www.youtube.com/watch?v=apyBGTAuGgg.
Formalin is banned for use as a preserving material in all schools, universities and museums in Europe and is only used under very strict conditions in research establishments.
In Norway it is used without any protective equipment for workers in the seaweed industry, in fact the industry plays down its use as it is the only chemical they can use to prevent the release of deadly hydrogen sulphide from decomposing stored seaweed.
The industry is now currently run by Dupont in Norway, having taken over from FMC a couple of years ago.
Dupont is currently under investigation in the us over possibly the worlds largest pollution scandal involving.