The coroner investigating the death of a 59-year-old Somerset woman said there was a "very real possibility" that Britain's worst mass water poisoning had been a contributing factor.
Carole Cross, from Dulverton, died at Taunton's Musgrove Park Hospital in 2004, and she was found to have a high amount of aluminium in her brain.
Mrs Cross had been living in Camelford, North Cornwall, when aluminium sulphate was accidentally added to the wrong treatment tank in 1988, polluting the drinking water.
Speaking at Mrs Cross' inquest in Taunton this morning, West Somerset coroner Michael Rose said there was insufficient evidence to say conclusively that the poisoning caused her death.
Recording a narrative verdict, Mr Rose said she had been exposed to "an excessive amount" of aluminium in the contaminated water, and that there was a "very real possibility" the ingestion of aluminium contributed to her death.
Mr Rose added that the South West Water Authority was "gambling" with the lives of up to 20,000 people by not informing the public about the poisoning for 16 days.
The accident occurred when a delivery driver mistakenly tipped 20 tonnes of aluminium sulphate into the wrong tank at Lowermoor treatment works.
The chemical - a highly acidic cleansing agent used to treat cloudy water - went straight into the area's mains water supply.
Soon after the incident, people began to report numerous health issues such as stomach cramps, rashes, diarrhoea, mouth ulcers and, in some cases, hair turning green from copper residues.
Mrs Cross and her husband Doug later moved to Dulverton. When she died in 2004, she had cerebral amyloid angiopathy (CAA) - usually associated with Alzheimer's.
The inquest had heard from Dr Chris Exley, a professor of bioinorganic chemistry at Keele University, who said there were "record levels" of aluminium in Mrs Cross' brain.
The coroner has called for more research into effects of the poisoning incident on public health.