Recently, a customer who had purchased several CFL bulbs, called to ask this question. The first thing I asked was how many bulbs were broken and if the shattered glass was dispersed. In his case about 2-3 were broken and the shattered glass was contained. This is harmless. His biggest concern was the mercury that might have contaminated his apartment. This really isn’t an issue since CFLs contain such a small trace amount of mercury. Effective April 15, 2007, participating members of National Electrical Manufacturers Association (NEMA) agreed to voluntarily cap the total mercury content in CFLs at less than 25 watts at 5 milligrams (mg) per unit. CFLs that use 25 to 40 watts of electricity will have total mercury content capped at 6 mg per unit.