A team of Yale scientists and the Department of Energy both calculate that switching to CFLs will decrease the total amount of mercury released into the environment. Even though the bulbs themselves contain mercury, that amount is much less than would have been emitted into the air by coal power plants to produce electricity for a normal incandescent bulb.
And that's the worst-case scenario where the CFL bulbs don't get recycled. By recycling them you can reduce the "landfill" portion of those mercury emissions to zero! Good thing there are so many places in Omaha and Lincoln that accept burned-out CFLs for recycling.
To know more about mercury emissions and your lighting options...
