[Demosthenes]

exactly how is it nasty and toxic?

[Poohbah]

You're sandblasting paint. The paints used on submarine hulls have some special properties (which I'm not at liberty to discuss). Those properties come at the price of the paint being very bad for you if inhaled--and respirators won't stop all of it, you need a "space suit."

[Redcloak]

Some of the materials on a sub's hull are toxic. Others become toxic if burned or overheated during removal. Application and removal are both processes where a careless, or untrained, worker can be exposed to toxic materials.

[gwynapnudd]

"exactly how is it nasty and toxic?"

Marine paint is still lead based paint. Breathing sanded particle can kill ya quick without the proper safety equiptment. Lead is the only base that can protect against barnicles. They make it at American Chemet in Helena, Montana.

I believe Hiway paint is still lead based too.

[PeoplesRepublicOfWashington]

Sandblast grit and old paint are regarded as hazardous wastes. But then again, so is table salt.