PARIS -- Asian candles are tainted with so much lead that burning them may spread toxic particles throughout the home, according to research reported in today's **** New Scientist ****.

Lead is added to the candle wick to stiffen it and give it a more even burn, and it has long been known that toxic particulates may be released into the air around the candle flame.

However, researchers at the United States' Environmental Protection Agency (EPA) have discovered that burning a leaded-wick candle raises particulates not just near the candle but throughout the house.

In a test of eight leaded-wick brands, they found that burning just one candle for only four hours raised lead levels in that room to 6.2 micrograms per cubic meter and two micrograms per cubic meter throughout the rest of the house, the British weekly says.

The maximum permitted level under U.S. air quality standards is 1.5 micrograms per cubic meter.

The worst candle would raise lead levels in the room where the candle is burned to more than 13 times the safety level, the scientists found.

The research is to be published in a future issue of a specialist journal, **** The Science of the Total Environment ****.

The **** New Scientist **** report did not identify the candle brands or say which countries manufactured them, describing them only as having been made "in the Far East." It noted that all U.S. and Western European manufacturers are committed to using safer but more expensive alternatives to lead such as zinc, and that the United States is studying plans to outlaw leaded-wick candles, AFP reported.

Lead is toxic, especially for children, because it hampers brain development.

Sales of imported candles in the United States market have grown by 800 percent since 1992, and are now running at some three million per year.