Compact fluorescent light (CFL) bulbs are an economical and environmentally friendly alternative to the traditional incandescent light bulb. They consume less energy and last longer than traditional bulbs. However, CFL bulbs contain mercury vapor which may pose a health risk if handled improperly.
A study conducted by Li and Jin at Jackson State University sheds light on the potential risk (2011). Most CFL bulbs contain between 0.1-3.6mg of mercury. This toxic metal is very well contained in the bulb housing with less than 4% leaching out, well below US safety standards. The problem arises if the bulb is broken. Li and Jin calculated that the mercury vapor is released in the air and can persist for up to 10 days. The total mercury exposure can exceed acceptable levels and pose a health risk.
What can you do to minimize your risk? Be very careful when handling and storing CFL bulbs to minimize the possibility of breakage. If a CFL bulb does break, remove it immediately and ventilate the area for several days. Be careful when discarding used CFL bulbs. Many states in the US and the EU require special disposal of CFL bulbs. The US EPA recommends that you double bag the CFL bulbs, but the mercury vapors can still leach out of the bags. The best option is to discard the bulbs in a sealed, glass container, like an old mayonnaise jar. This is will also reduce the chances that the bulb will break in the waste container or landfill.