The former Powertrain plant at Longbridge has been revealed as the site of the largest single outbreak of occupational asthma. So far 101 workers have been diagnosed with lung disease.

The Health and Safety Executive has today given an update on the outbreak at the former car plant which was first identified in March 2004.

The workers are suffering from either occupational asthma or extrinsic allergic alveolitis. Occupational asthma can cause attacks of wheezing, coughing, chest tightness or shortness of breath. Extrinsic allergic alveolitis can cause coughing, breathlessness, chills, sweats and joint pain, which may feel like a bout of flu. There may also be weight loss. Some breathing difficulty can be long term.

Sandra Caldwell, director of HSE's field operations said today: "The outbreak at Powertrain is thought to be both the world's largest linked to metal working fluids, and the largest single outbreak of occupational asthma.

“It has changed the perception of the risk arising from the exposure to mist from metalworking in the UK. We are determined that workers elsewhere in this sector should get better protection against contracting these diseases, which have the potential to seriously impair the breathing and health of those affected by them.

"We know that the cause of the disease was mist from metalworking machines, which was widespread throughout the factory. While we do not know the precise agent within the mist that triggered the outbreak, we did find links to bacteria, and used metalworking fluid. Other possible causes, such as metals leaching into the mist from the machining and washing of components, have been closely investigated and are thought unlikely to have caused the outbreak."

As a result of the outbreak HSE has updated its guidance on metalworking and this is now available at www.hse.gov.uk/metalworking.

HSE served three improvement notices on Powertrain Ltd in 2004 once the scale of the outbreak became apparent. The notices required Powertrain to take action in line with the increased risk and they were complied with. The company went into administration in 2005 and the assets were subsequently sold to Nanjing Automobile and taken to China. No further action is proposed by HSE.