There's also a much longer list of 1,100 bulbs it urges consumers to avoid because they don't meet stricter Energy Star standards that are expected to go into effect in July. These standards were supposed to take effect last year, but the EPA gave bulb makers a grace period for chipping away at a stockpile of 100 million bulbs they have that don't meet the new standards. Along with obscure or foreign-made brands I've never heard of and probably wouldn't buy anyway, these blacklisted bulbs include products that are sold at Wal-Mart ( WMT), Lowe's ( LOW) and Home Depot ( HD) or made by major manufacturers like General Electric ( GE), Siemens ( SI) and Philips Electronics ( PHG). The other issue with CFLs is that they contain mercury, and while it's not a lot, the EWG claims it's often more than necessary. The new Energy Star standards put a cap on mercury content for the first time. That cap is 5 milligrams -- roughly enough to cover the tip of a ballpoint pen, according to the EPA. For context, an old-fashioned mercury thermometer contained about 500 milligrams of the stuff. The watchdogs at the EWG warn that one-third of bulbs on the market don't meet this standard. But they also say that manufacturers have been way ahead of the EPA on ratcheting down the mercury milligrams. National Electrical Manufacturers Association set a voluntary cap of 5 milligrams a few years ago and a lot of its manufacturers have done better than that. EPA and NEMA concur that the industrywide average for mercury in CFLs is 3 to 4 milligrams. The safest bulbs have 2.7 milligrams or less.