The subgroup, who have released a new report into the Camelford incident say further work is needed to look at the health of children born to women who were pregnant at the time of the pollution.
It happened in 1988 when 20 tons of aluminium sulphate was dumped into the wrong tank at a water treatment works at Lowermoor.It went directly into the local water supply.
Last year an inquest into local resident Carole Cross revealed high levels of aluminium found in her brain.
She died from a rare form of alzheimers and her family believe the water pollution led to her death. A coroner at her inquest said it was possible but there wasn't enough evidence to say so conclusively.
This latest report said they did not find a conclusive link.
Our research indicates that it is unlikely that the relatively short term exposure to chemicals from this incident would have caused long term health effects among local people. However, work on potential long term neurological effects is needed because of problems with the design of previous studies and to follow up an unusual case of dementia in an individual who lived in the Lowermoor water supply area at the time of the incident.