AIR BAGS, which protect drivers and passengers in car accidents, could cause permanent loss of hearing or ringing in the ears after a crash, according to new research.

Researchers from Leeds General Infirmary, St James's University Hospital in Leeds and the Vehicle Safety Research Centre in Loughborough believe that the noise generated when air bags inflate - which can be up to 170 decibels - could damage the ears.

Their findings, published today in the British Medical Journal, are based on two cases in which drivers suffered hearing loss and persistent tinnitus which they believe may have resulted from air-bag inflation in low-speed collisions.

In one, a 38-year-old woman was involved in a collision in the United States while driving at about 20mph. The air bag struck her in the face and she noticed an immediate hearing loss, tinnitus and unsteadiness, the report says. Tests showed permanent hearing loss in the inner ear.

In the other case a 68-year-old man drove into the back of another vehicle at about 15mph. The air bag inflated and he complained of an immediate "bilateral" hearing loss and tinnitus. A test confirmed that his hearing had been impaired.