sstorkel

Volatile Organic Compounds. This is the stuff that kills brains cells and gives you cancer when you breathe it in. VOCs can also pollute air as well as damaging soil and ground water. Not surprisingly, Google will give you lots more info if you're interested...

To the OP: it wouldn't surprise me if commercial painters are being forced toward low VOC paint no matter what they're painting; environmental regs are tightening across the country. Rattle cans are probably exempt because they figure you can't afford to buy enough of them to harm anyone but yourself