Energy-saving light bulbs are so dangerous that everyone must leave the room for at least 15 minutes if one falls to the floor and breaks, a Government department warned yesterday.

The startling alert came as health experts also warned that toxic mercury inside the bulbs can aggravate a range of problems including migraines and dizziness.

And a leading dermatologist said tens of thousands of people with skin complaints will find it hard to tolerate being near the bulbs as they cause conditions such as eczema to flare up.

The Department for Environment warned shards of glass from broken bulbs should not be vacuumed up but instead swept away by someone wearing rubber gloves to protect them from the bulb's mercury content.

In addition, it said care should be taken not to inhale any dust and the broken pieces should be put in a sealed plastic bag for disposal at a council dump – not a normal household bin.

None of this advice, however, is printed on the packaging the new-style bulbs are sold in. There are also worries over how the bulbs will be disposed of.

The 'green' light bulbs which will be made compulsory in British homes can cause people with epilepsy to experience symptoms similar to the early stages of a fit.

The charity Epilepsy Action says that those with the condition are complaining of dizziness, loss of focus and discomfort after being exposed to light from the energy-saving bulbs. The cause of the problem is not known as the bulbs do not flicker at the rate that would normally cause ill-effects.

But the issue has become prominent because of EU plans to phase out all traditional bulbs within two years and replace them with low-energy versions. Almost half a million people in the UK suffer from epilepsy and the Government has acknowledged there may be a problem.