Wow, more poisons in our world, in our water and earth. From a tiny flaw in a CFL light bulb:

CFLs are marketed as “safe” and don’t pose any health risks as long as the glass remains intact. The danger comes if the bulbs are cracked, broken or not disposed of properly. Although it sounds like a miniscule amount – 4 to 5 milligrams – there is enough mercury in just one fluorescent light bulb to contaminate 6,000 gallons of water. So what does that mean if a CFL is cracked or breaks in our homes, releasing mercury vapors in an enclosed area? Consumers – especially those with young children –need to know what to do when a CFL breaks and the proper way to dispose of used bulbs. It’s no longer as easy as changing a light bulb. Mercury Warning: Compact fluorescent light-bulbs contain very small amounts of mercury and care must be taken in disposing of them or when they break. The EPA suggests the following: o People and pets should immediately leave the room. o Open a window and/or door and Air out the room for 5 to 10 minutes. o Turn off the central forced air heating/air-conditioning system. o Thoroughly collect broken glass and visible powder using wet cloths. Never use vacuum cleaners or brooms. o Put all debris and cleanup materials in a sealable container and put outdoors in a trash container or protected area until materials can be disposed of properly. Do not leaving bulb fragments or cleanup materials indoors. o If practical, continue to air out the room where the bulb was broken and leave the heating/air conditioning system shut off for several hours.

Source: Understanding The Dangers of Compact Fluorescent Light Bulbs | Wake Up World