When I was with Schlumberger fracking was/is done using a mixture of hydrochloric (HCl) and hydrofluoric acid (HF) AKA Mud Acid.
Put this stuff in a glass jar and it melts it.....
We could not get it in the Netherlands so got it from Germany transported in special tanker trucks.
One time, out in the field, saw a guy get really badly burnt with this stuff, we chucked him under one of the portable showers we had on site exactly for this reason when using the stuff.
Loading up one of our stimulation boats one time and a hose connection was leaking, the dead fish soon came to the surface.
Yes folks, this stuff gets pumped into the ground and could, in theory, get in the water supply.
Now that Redline is what I call a proper HSE e.mail......