The legal action was started after a scientist said the number of cancer deaths among people living near the plant in Essex appeared to be significantly higher than the national average.
The company, Pan Britannica Industries, which runs the factory, denies that there is any basis for suggestions that there are cancer clusters among local residents.
Solicitors acting for more than 100 residents said they wished to investigate the possibility of any link between pesticide exposure and the cancers.
The residents are also seeking compensation for what they say are the noxious fumes and smells often released from the plant at Waltham Abbey. According to a recent television documentary, 17 people in the two streets nearest the plant have died from cancer in the past 10 years.
The Carlton Television programme, Storyline, also reported that at least three people had developed brain tumours in the last decade; normally, three such cases would only be found in a small area over a 200-year period, according to scientists.
Further, researchers said that at least seven workers at the factory had developed cancer since 1982.
Richard Meeran, the residents' solicitor, said: 'This is something which is very disturbing.'
Tony Fletcher, a senior lecturer in environmental health policy at the London School of Hygiene and Tropical Medicine, said the figures showed 'an apparent excess of cancer' both among people living near the plant and among its workers. However, he added: 'There is sufficient evidence to justify a systematic scientific investigation, but there is not sufficient evidence to justify shutting the plant down while waiting for the results.'
Some of the pesticides that have been produced at the plant, such as Dimethoate, have been shown to be carcinogenic in animals, although none had been proved to cause cancer in humans, scientists said yesterday.
Mr Meeran also said the residents would sue for damages as the result of the pungent smells and dust frequently emitted by the plant.
Last year, people living around the factory said the odour from the accidental release of a non- toxic chemical, methyl mercaptan, was so strong that they were sick and had to go to hospital.
Residents have launched a petition calling for a public inquiry.
Last night, Jeremy Tear, managing director of PBI, which is owned by the Japanese Sumitomo Corporation, said there was 'no statistical evidence of an increased incidence of cancer. The allegations made are outrageous and have been refuted by our medical consultant'.
He added that no official body charged with regulating the plant, such as the Health and Safety Executive or Her Majesty's Inspectorate of Pollution, had 'shown cause of concern regarding our activities'.