Published March 25, 2014 • Updated on March 25, 2014 at 2:31 pm (NECN: Tom Langford) - They're showing up at hardware stores across New England. And one look at the packaging tells you why they're becoming popular. Compact florescent lightbulbs -- known as CFLs -- can deliver big savings on your energy bill. In fact, they're so good, the government is mandating the phase out of traditional incandescent bulbs, in favor of energy-efficient bulbs, such as CFLs. But what's less publicized, and less popular, is on the back of the package. CFLs contain mercury -- a dangerous toxin that can effect your nervous system. And if one breaks, mercury is released into your home. That's what happened to Tom Heim. And when his bulb broke, he did was most people would do -- he vacuumed it up.