Toughened glass is not reducing injuries among people in bars - because there is no industry standard that manufacturers have to conform to.

A study published in Injury Prevention (2000;6:36-40) has found that staff are more likely to injure themselves with new, toughened glasses. The authors emphasise that this does not mean that bars should return to the old annealed glasses, but that there must be a minimum standard for the new ones.

Professor John Shepherd, leader of the Violence Research Group at the University of Wales, the main author of the study, said that toughened glass was "certainly the way forward in reducing injury and violence."

Altogether 3500-5500 people are injured a year in so called "glassings." Awareness of attacks was raised after a 1997 campaign led by Glenda Jackson, whose son lost an eye in a bar brawl. There is support in the Scottish Parliament for legislation to try to reduce attacks but little activity south of the border.

Professor Shepherd estimates that around 30-40% of bar glasses are now made of the toughened glass. The glass disintegrates into small cubes, similar to a shattered car windscreen. The old glasses form jagged shards that are easy weapons in a fight. Nevertheless, any manufacturer can claim that their glass is "toughened", and publicans want the security of a kite mark.

Injuries were 60% higher among those using toughened glasses, although there was great individual variation. The study showed that less force was required to break the toughened glasses, partially explaining the increase in injury. There were also complaints that the glasses spontaneously disintegrated on shelves. Bar staff, however, expected the new glasses to be "unbreakable," or harmless when broken, and may have treated them with less care.

Over 1200 bar staff in 57 bars and pubs in England and Wales took part in the randomised controlled trial. All pint glasses were replaced with either annealed or toughened glass and staff recorded any injuries from handling the glassware over a six month period.