Water system experts testified Tuesday on the second day of a class-action lawsuit against the U.S. government that tests may have missed contamination in the critical early days of the Red Hill fuel crisis.

The trial in federal court in Honolulu involves the first 17 plaintiffs claiming medical, emotional and financial injuries from the contamination. Another roughly 7,500 plaintiffs have joined other lawsuits also seeking compensation. The crisis began in November 2021 when jet fuel from the Navy’s underground Red Hill fuel storage facility tainted the Navy’s Oahu water system, which serves 93,000 people including service members, military families and civilians living in former military housing.

Government lawyers have argued that the amount of jet fuel that entered the water system was relatively low — too low to make most people sick — and that many people who reported symptoms weren’t exposed to fuel at all. They argue the ailments reported by thousands of people were stress-induced from hearing about contaminated water rather than from the contaminated water itself.

But Joseph Hughes, an engineering professor at Drexel University in Philadelphia, testified Tuesday as a witness for the plaintiffs and argued that contamination levels could be higher than the federal government acknowledges and that it would have spread quickly through the system.

On May 6, 2021, at least 20,000 gallons of JP-5 jet fuel spilled from one of Red Hill’s underground storage tanks, entering the facility’s fire suppression system. On Nov. 21, 2021, a worker driving a cart accidentally ruptured a pipe in the system, spilling the fuel in a tunnel near the Red Hill water well, which served the Navy waterline.

Navy officials responded and believed that they had contained the spill, and decided not to tell their superiors or state regulators. In the coming days, people on the waterline began reporting smelling fuel in the water and experiencing wide-ranging symptoms such as coughs, rashes and vomiting. The Navy shut off the well from its system on Nov. 28, 2021, and during the first months of 2022, the entire system was flushed.

Hughes testified that there were two types of testing carried out by the Navy after the November spill — “low flow” sampling and “bailer” sampling. Low-flow sampling is designed to take samples out of the water with minimal disruption to the water itself in an effort to minimize outside influences. Bailer sampling involves putting a sampling tube in the water and trapping a sample.

Hughes said that no bailer samples were taken from the Navy’s water system before the Navy shut down the Red Hill water well Nov. 29. He said that means potential contamination may have been missed because jet fuel is a light nonaqueous phase liquid — or LNAP — meaning it is less dense than water and tends to rise to the surface.

Hughes argued that low-flow sampling could have missed fuel closer to the water’s surface, which would have been captured by bailer sampling. He also said the higher concentrations likely would have been found in samples that did find contamination if those tests had been conducted earlier.

Under cross-examination from the government’s attorneys, Hughes acknowledged that not all the fuel that spilled into the Red Hill water well made it into the Navy’s drinking water system. The lawyers cited the accounts of Navy divers who were sent into the well as part of the response who reported that fuel was still seeping from the lava rock into the water well after the Navy shut it off from its water distribution system.

But Hughes said that based on his modeling of government data, he believes over 2,000 gallons of fuel entered the system from the contaminated Red Hill well before it was shut off. He told the court that “a little bit of volume is a lot of mass” when it comes to contamination of this sort.

Government lawyers questioned his credentials, noting he is neither a medical doctor nor epidemiologist, and that he was only analyzing data and wasn’t involved in any of the testing itself.

During the first and second day of the trial, Patrick Feidnt, a plaintiff in the trial, and his wife, Army Maj. Mandy Feidnt, testified about the symptoms they experienced. The government’s lawyers asserted that their home on Ford Island was never exposed to fuel and presented test results from their home. When presenting it to Mandy Feidnt, she testified it was the first time she had ever seen the document despite asking for it for years.

The government’s lawyers maintain that their symptoms during the crisis — including severe rashes, vomiting, diarrhea and other ailments — were all the result of preexisting conditions or stress-induced and cannot be tied to JP-5 fuel.

The Feidnts described the symptoms their young children suffered, including their daughter who still suffers neurological and psychological problems. They acknowledged that she had developmental problems from before the spill, but said the exposure to the fuel and the trauma it caused has exacerbated behavioral problems. They testified that their daughter now fixates on water and is scared of it, associating nearly all illnesses with drinking water.

The trial will continue through next week. Outside the courthouse Tuesday, the state Department of Health announced that it has rejected the Navy’s Red Hill Consolidated Groundwater Sampling Program as the military works to close the facility. The Navy has been monitoring groundwater for fuel while dumping treated water from the Red Hill well into Halawa Stream.

In a media release the DOH said it ordered the Navy “to implement a modified version of the program, which includes additional conditions relating to groundwater monitoring to support the Navy’s request to reduce the amount of water being discharged into Halawa Stream from 4.5 million gallons a day to 1.8 million gallons a day.”

“We have worked to hold the Navy accountable to create its own plan to reduce the amount of water discharged into Halawa Stream, while still maintaining a robust sampling program to track and stay ahead of any contaminant migration,” said Deputy Director for Environmental Health Kathleen Ho in a statement. “It’s unacceptable that the Navy would fail to produce such a plan following multiple rounds of regulatory review. That’s why we are taking the unusual step to reject the Navy’s plan and impose conditions necessary to protect public health and our environment.”