A group of residents concerned that mercury from a former pesticide plant in Hachioji, western Tokyo, is making locals sick called on the Environment Agency and the Tokyo Metropolitan Government on Friday to check the surrounding environment for pollution and citizens for health problems.

The petition also calls on the government to stop the mercury cleanup project now under way until it can be confirmed that it is not spreading mercury or other chemicals into the surrounding residential area.

The citizens sent a similar petition to Nihon Bayer Agrochem, which owns the property and is trying to clean up the mercury pollution, requesting a reply by the end of the month.

The activists said many locals have suffered from an assortment of strange symptoms, including numbness of the limbs, headaches and ringing in the ears since the cleanup project started in April.

The group also said that surveys of soil near the former chemical factory yielded 3.15 parts per million of mercury -- exceeding the nonbinding environmental guidelines of both the metropolitan government and the Environment Agency.

Studies of local residents' hair analyzed domestically and in the United States also showed values above those deemed safe by the U.S. government.

Company officials were unavailable for comment.