Good point that.. Could they be ground back to made safe?
Yes. Reworking cold chisels is standard job for a blacksmith. Years ago I worked with a maintenance/odd job team in a carpet factory. It was a big place and they had a welding shop and a machine shop. The blacksmith had his forge in a corner of the machine shop. A couple of times I had to take about a dozen cold chisels to the blacksmith and it was a sight to see. He'd heat them up. Hammer them to make them longer, re-temper the shaft, redo the cutting edge with a grinder, re-temper the very tip. Get it warm again in the forge and dip it in some black stuff. The last part was finally grinding the cutting edge through the black stuff and grinding the hammering end neat.
It's been 40 years ago, so I may have mis-remembered some of the details.