Energy-saving light bulbs were at the centre of a fresh health scare after researchers claimed they can release potentially harmful amounts of mercury if broken.
Levels of toxic vapour around smashed eco-bulbs were up to 20 times higher than the safe guideline limit for an indoor area, the study said.
The European Union is phasing out the traditional “incandescent bulbs” used for more than 120 years and is forcing people to switch to low-energy alternatives to meet its climate change targets.
A CFL uses a fifth of the energy of a conventional bulb and can save £7 a year in bills. However, critics complain that CFLs’ light is harsh and flickery. Medical charities say they can trigger epileptic fits, migraines and skin rashes and have called for an “opt out” for vulnerable people.
Incandescent bulbs do not contain mercury, along with other variants of energy-saving lights, such as LEDs and halogen bulbs. The study, for Germany’s Federal Environment Agency, tested a “worst case” scenario using two CFLs, one containing 2 milligrams of mercury and the other 5 milligrams. Neither lamp had a protective casing and both were broken when hot.
Scientists at the Fraunhofer Wilhelm Klauditz Institute found that they released around 7 micrograms (there are 1 000 micrograms in a milligram) per cubic metre of air.The official guideline limit is 0.35 micrograms per cubic metre.
Federal Environment Agency president Jochen Flasbarth said: “The presence of mercury is the downside to energy-saving lamps. We need a lamp technology that can prevent mercury pollution soon.
“The positive and necessary energy savings of up to 80 percent as compared with light bulbs must go hand in hand with a safe product that poses no risks to health.”
During tests the German government agency’s researchers were alarmed to discover that some bulbs had no protective cover and broke when hot.
High levels of mercury were measured at floor level up to five hours after the bulbs failed.
A spokesman for the agency said: “Children and expectant mothers should keep away from burst energy-saving lamps.
“For children’’s rooms and other areas at higher risk of lamp breakage, we recommend the use of energy-saving lamps that are protected against breakage.”
However, the UK Government insisted the CFL bulbs were safe – and that the risk from a one-off exposure was minimal.
The Health Protection Agency says a broken CFL is unlikely to cause health problems.
However, it advises people to ventilate a room where a light has smashed and evacuate it for 15 minutes.
Householders are also advised to wear protective gloves while wiping the area of the break with a damp cloth and picking up fragments of glass. The cloth and glass should be placed in a plastic bag and sealed.
CFLs are not supposed to be put in the dustbin, whether broken or intact, but taken as hazardous waste to a recycling centre.
A spokesman for the Department for Environment, Food and Rural Affairs said: “The mercury contained in low-energy bulbs does not pose a health risk to anyone immediately exposed, should one be broken.”
Friends of the Earth said the switch to low-energy bulbs would reduce exposure to mercury from coal-fired power stations.