Military and civilian families who drank and bathed in fuel-tainted water after a fuel spill at the Navy’s Red Hill facility in November 2021 contaminated their drinking water, were also exposed to antifreeze, according to an internal Hawaii Department of Health memo that identifies the coolant as potentially posing the biggest health risk.

The compound in the antifreeze, diethylene glycol monomethyl ether, is used in aviation fuels to help prevent the formation of ice crystals. It was detected in water samples collected in the weeks after jet fuel spilled from a Red Hill underground pipeline and made its way into the Navy’s drinking water system that serves about 93,000 people.

The Feb. 2 memo from DOH provides estimates of contaminants that entered the drinking water system, including additives that the Navy put in its jet fuel.

The antifreeze compound “would have been quickly drawn into groundwater in contact with JP-5 (jet fuel) and is likely to have entered the Red Hill Shaft drinking water system ahead of less soluble and less mobile, petroleum contaminants,” according to the DOH memo from Roger Brewer of DOH’s Hazard Evaluation and Emergency Response office, which was sent to the state toxicologist and chief of DOH’s Safe Drinking Water branch.

Brewer writes that the compound “could pose the most significant health risk from exposure to contaminated water.”

Approximately 10,000 households are believed to have been affected by the jet fuel contamination and hundreds reported symptoms including vomiting, diarrhea, burning in their mouth and throat, chemical burns, skin rashes, seizures, dizziness and fainting. Some people reported that their pets got sick and died.

The DOH memo was provided to the Star-Advertiser this week by attorneys for military families who are suing the Navy over the jet fuel exposure. In an amended complaint filed on Monday, they argue that the Navy never informed families that this additional toxin was present in their contaminated water.

Some of those exposed to contaminated water have said that they continue to suffer long-term health effects and have accused the military of gaslighting them by not taking their symptoms seriously.

“This amended lawsuit adds to the story of a government that poisoned its people, failed to treat them, and told sick families they were not sick,” Attorney Kristina Baehr, a lawyer for the families, said in a press release related to the amended complaint. “The fight goes on to hold the government accountable for its conduct before, during and after the Red Hill contamination. These families still do not know what exactly was in the water they ingested and bathed in for months.”

DOH said that while attorneys for the Red Hill families refer to the substance as antifreeze, it should not be confused with car antifreeze, which is more toxic. DOH said thatdiethylene glycol monomethyl ether may have played a role in the symptoms experienced by Red Hill families, but that it didn’t have data on how much was present in drinking water to draw conclusions.