Why you should hold your breath if you break a compact florescent bulb

There is a big downside to "green" compact florescent bulbs. Broken compact fluorescent light bulbs can exceed safe exposure levels for humans of mercury vapor into the air. The out-gassing continues for weeks. Put these bulbs into an outside trash receptacle immediately.

ScienceDaily — Once broken, a compact fluorescent light bulb continuously releases mercury vapor into the air for weeks to months, and the total amount can exceed safe human exposure levels in a poorly ventilated room, according to study results reported in Environmental Engineering Science, a peer-reviewed online only journal published monthly by Mary Ann Liebert, Inc.

The amount of liquid mercury (Hg) that leaches from a broken compact fluorescent lamp (CFL) is lower than the level allowed by the U.S. Environmental Protection Agency (EPA), so CFLs are not considered hazardous waste. However, Yadong Li and Li Jin, Jackson State University (Jackson, MS) report that the total amount of Hg vapor released from a broken CFL over time can be higher than the amount considered safe for human exposure. They document their findings in the article "Environmental Release of Mercury from Broken Compact Fluorescent Lamps."

As people can readily inhale vapor-phase mercury, the authors suggest rapid removal of broken CFLs and adequate ventilation, as well as suitable packaging to minimize the risk of breakage of CFLs and to retain Hg vapor if they do break, thereby limiting human exposure.