Lawsuits may be filed as early as 3pm (EST) on Friday, the lawyers have said. Several retailers could be targeted, following independent lab tests for bromate in private label bottled water brands they sell.
The warning follows recalls on some waters in New York, including one from the Wegmans retailer and also the Food Club brand, because they contained bromate above the legal limit in the US.
Long-term exposure to bromate may increase consumers' risk of cancer, according to the US government's Environmental Protection Agency.
After Wegmans, BeverageDaily.com revealed last week that more recalls were planned and the problem was suspected to have come from a common source, Springbrook Springs.
Wegmans was first alerted to a problem by independent lab tests, which claimed to have found bromate levels in the drink at 27 and 28 parts per billion (ppb). The FDA maximum is 10ppb.
Ross Getman, a lawyer and the man behind the independent lab tests for bromate in water, said tests were also done on a range of brands and that several retailers had been informed of a potential problem.
He said lawsuits would be justified if some took no action before Friday. "A full month [for them] to conduct independent sampling is quite enough."
Any lawsuits filed could see bottled water firms embroiled in a similar battle to the one currently being fought by other soft drinks firms over allegations of benzene residues in drinks.
Wegmans, in pulling its Food You Feel Good About Spring Water, has publicly warned other retailers they may find a problem with bromate in waters produced by the same supplier.
FDA scientists have been working with firms to investigate the problem.
The International Bottled Water Association (IBWA) refuted suggestions that its members' products were unsafe this week. "The current system of bottled water regulation provides consumers with outstanding bottled water safety, quality and public health protection."
It said it supported Food and Drug Administration (FDA) standards and that the recent recalls proved that the current regulatory system protected consumers. "Consumers can remain confident in making bottled water their beverage of choice."
Guidelines on how to avoid bromate in water have been published by the International Ozone Association.