The blast of the vuvuzela plastic horns at World Cup matches is so loud that people in close proximity could suffer hearing damage, experts said.

The sound emitted by a vuvuzela is equivalent to 127 decibels, according to a South African survey.

That makes it louder than a drum's 122 decibels, a referee's whistle at 121.8 decibels - and close to the noise of a jet taking off at 300 metres, which is around 130 decibels.

Sound bursts at such high levels "are catastrophic" for hearing, as they destroy hair cells in the inner ear, of which there is a small and non-renewable population of only 15,000, said French specialist Mireille Tardy.

Decibels are measured on a logarithmic scale, which means that every 10-point rise in the scale reflects a tenfold increase in intensity.

At a distance of two metres (six feet), "10 vuvuzelas will be 10 decibels higher and 100 vuvuzelas 20 decibels higher" than a single horn, said Christian Gelis, a professor of biophysics.

"To be exposed to this type of volume raises the risk of immediate inner-ear trauma," with lasting damage to hearing, said Gelis.

At such levels, wearing good-quality earplugs that reduce the noise by 20 decibels will eliminate the worst risks but still not bring the wearer into the safety zone, said Gelis and Tardy.

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