Compact fluorescent light bulbs have contained very little mercury for a long time now, with the already small amount continually decreasing as technology improves. Original EPA guidelines for dealing with broken CFLs were blown a bit out of proportion, and they are now offering revised guidelines.
Common contemporary compact fluorescent light bulbs
contain about 4mg of mercury per lamp. Most of that 4mg coats the inside of the glass tubing and is not released from a broken bulb. The EPA's revised tips indicate that the tiny amount of vaporized mercury from a single broken bulb is within the safe range for adults. It's heartening to see a government agency providing sound, reasonable information instead of the unnecessarily excessive info they previously gave.
That's not to say CFLs are off the hook with respect to mercury. It's still extremely important to dispose of them properly, be it through recycling or safe destruction. Mercury buildup from millions of CFLs in landfills would indeed be very poisonous and negatively impact the environment. Correctly recycled and/or destroyed CFLs pose no threat to humans or the environment, and as such they remain the top cost-effective energy efficient lighting technology for consumers.
LED light bulbs and other energy efficient lighting technologies are continually being improved, and in time will overtake the popularity of CFLs. The prices of LED technology are dropping pretty consistently every year, in some cases by 15% to 20%. Until then, compact fluorescent light bulbs are a safe, inexpensive energy efficient light source for everyone.