Staff at De Montfort University are suing their employer alleging negligence because of a chemical leak which they claim has caused them brain and nerve damage.
A writ should be served next week by the trade union, Unison, representing 14 staff. Other staff are suing separately. Unison is also trying to trace staff and students who worked at the university at the time of the leak but may be unaware of alleged long-term consequences of exposure to the chemicals.
The leak occurred in a chemical store at the university over a weekend in October 1991. A mixture of chemicals escaped, releasing enough heat to buckle metal shelving in the store, according to Unison lawyer Doug Brown. Unison also plans to sue Leicestershire Fire Service for its alleged mishandling of the release.
Staff from the chemistry department helped the fire brigade to clean up the area. They also checked the storeroom and listed more than eight chemicals, gas and liquid, that had been released. Unison says that staff symptoms were initially nausea and eye and chest irritations.
Several months later some staff who had been exposed to the chemicals developed psychological problems such as short-term memory loss and irritability.
They have been examined by a clinical psychologist and a neurophysiologist who have confirmed that they show apparently similar patterns of brain damage, the union says.
Sufferers include a senior laboratory technician and a PhD student. The student "will probably never be able to work or study", according to a Unison statement.
The university said that, through its insurers, it will "deal as sympathetically as possible with those who feel they have been affected by the incident".
The Health and Safety Executive did not investigate the incident.
Mr Brown defended the length of time taken to launch the suit. "We have had to get psychological reports and find the right expert," he said. "We are on the forefront of chemical science, dealing with some chemicals whose effects as a combination we do not know."