A jury found Ford negligent and awarded $US3.3 million to the seven-year-old son of a woman killed when the air bag of her Ford Taurus deployed in a low-speed accident, Associated Press (AP) reported.

Mayling Semidey, 29, a single mother, hit a concrete retaining wall at about 9 mph in 2000 and the air bag went off and caused fatal chest injuries, AP said.

The civil jury found the air bag system of her 1996 Taurus to be defective, the report said.

AP noted that the National Highway Traffic Safety Administration has investigated the risk of air bags to small-statured women and children who are close to the air bags when they deploy but added that Semidey was 5-foot-9 and was wearing a seat belt.

Richard Newsome, lead lawyer for the family, reportedly said older air bags can be problematic for people of any size if the victim is too close when it goes off.

According to Associated Press, the air bag in Semidey's 1996 Taurus was designed to go off in head-on crashes at 14 mph or faster, and not at speeds of 8 mph or less - at 9 mph, the air bag was designed to go off in some situations.

The family's lawyers argued that the air bag was defectively designed to go off in crashes slower than 10 mph when it was not needed, AP added.