People in north Cornwall hit by water poisoning in 1988 should have health checks as a former resident was found with Alzheimer's, a report says.
A toxic chemical was tipped into the wrong tank at the Lowermoor works
The suggestion is made in a Journal of Neurology Neurosurgery and Psychiatry study into the death of resident Carole Cross, which was published on Thursday.
Water supplies to 20,000 people in and around Camelford were contaminated when aluminium sulphate went into the wrong treatment tank.
A government inquiry is on-going.
About 20 tonnes of aluminium sulphate was delivered into the wrong tank at the former South West Water Authority (SWWA) water treatment works at Lowermoor in July 1988.
People across a large area of north Cornwall were exposed to levels of aluminium 500 to 3,000 times the acceptable limit defined by the European Union.
Camelford residents Douglas and Carole Cross moved to Dulverton, Somerset, two years after the incident.
The journal said Mrs Cross was referred to a neurologist in 2003 for repeated headaches, difficulties in finding words and doing simple sums, and hallucinations.
Her condition progressively worsened and she died in 2004, aged 59.
A post-mortem examination of her brain revealed a rare form of Alzheimer's disease. Very high levels of aluminium were also found in the affected areas of her brain tissue.
Mr Cross, a 67-year-old environmental scientist, said: "We have been demanding testing for 18 years, it is absolutely essential."
There could be other people there with conditions similar to those of his late wife but "nobody is looking", he said.
A report, published in January last year, said it was unlikely that the chemicals involved in the incident would have caused any persistent or delayed health effects.
But it recommended further research, including a study into those who did and did not drink the water.
The report's authors - Dr Chris Exley of Keele University and Professor Margaret Esiri of Radcliffe Infirmary, Oxford - recommended that residents should be tested to see if they have sustained any impairment to their intellectual capacity.
Dr Exley said a carefully planned monitoring programme of the health of the people was needed "so we can put their minds at rest".
In December last year West Somerset coroner Michael Rose adjourned the inquest into Mrs Cross' death to await the completion of further research.
After a trial at Exeter Crown Court in 1991 SWWA was fined £10,000, with £25,000 costs, for supplying water likely to endanger public health.
Three years later, 148 victims of the incident reached an out of court settlement, with payments ranging from £680 to £10,000.
A Parliamentary investigating committee is due to meet again in a couple of months, but no date has been given for the publication of the final report.