An Oakland-based environmental health group is threatening to sue the manufacturers and retailers behind two bottled water brands for failing to warn consumers about allegedly high levels of arsenic in their products.  

The Center for Environmental Health (CEH) has sent legal notices to Whole Foods, which owns the bottled water brand Starkey, and Keurig Dr. Pepper, which owns Peñafiel spring water, sold by Target. The center commissioned testing of the water brands and said it found both Starkey and Peñafiel contained arsenic levels high enough to warrant a health warning under California’s consumer protection law Proposition 65.

In the legal notices, CEH said it will file citizen lawsuits against Keurig Dr. Pepper and Whole Foods if they don’t agree to recall the bottled water already sold, pay a penalty, and either remove arsenic from the water they’re selling or place a warning to consumers on the bottles.

Peñafiel is bottled in Mexico, and marketed to the Latino community in the United States.

“People think of bottled water as a healthy drink, and compared to many things that you might drink it should be a healthy drink. But it shouldn’t have arsenic in it,” said Caroline Cox, senior scientist for CEH. “Companies have the responsibility to provide us with safe and healthy products.”

Arsenic is a toxic metal commonly found in untreated groundwater. Long-term exposure can cause cancer and skin lesions. It’s also associated with cardiovascular disease. Children are particularly vulnerable to arsenic contamination because their bodies and brains are still developing. Exposure to arsenic in early childhood and in utero is tied to lower IQ scores and increased deaths in young adults.

Cox compared arsenic exposure to the problem of lead exposure, which also disproportionately threatens the health of children and pregnant women.

“The thing that we’re really concerned about is the effect that arsenic can have on a child, if the child’s mother is exposed during pregnancy,” she said. “That’s really concerning.”

Citing legal reasons, CEH did not disclose the level of arsenic its testing detected in Starkey and Peñafiel. However, Cox said the levels were comparable to those found by Consumer Reports, which published an investigation in April on arsenic in bottled water. Consumer Reports said its own testing found Peñafiel samples registered average arsenic levels of 18 parts per billion, well above the federal limit of 10 ppb. Arsenic levels in Starkey water samples contained levels just under or slightly above the federal threshold, according to the publication.

Consumer Reports said the federal standard for arsenic levels in water should be lowered to 3 ppb because recent research on arsenic exposure suggests 10 ppb is too dangerous. California already sets a more stringent standard for arsenic than the federal government, although its recommended limit hasn’t been finalized, Cox said.

Keurig Dr. Pepper did not immediately respond to the California Health Report’s requests for comment. However, Keurig informed Consumer Reports earlier this week that it had suspended bottled water production at the Mexico Peñafiel bottling facility for two weeks, and that it plans to improve filtration of the water to remove arsenic. A spokeswoman said the company believes the current level of arsenic in the water does not post a health or safety risk to consumers.

Whole Foods, meanwhile, said that its own tests show that Starkey complies with federal standards for heavy metals.