The Port of Portland recently detected contaminated soil and groundwater at Portland International Airport, traced to a special foam used in firefighter training for more than a half-century.
So far, there's no evidence that the two chemical compounds, known as PFOS and PFOA, have spread very far. But the port is investigating the nature and extent of the contamination, and inked a voluntary cleanup agreement with the Oregon Department of Environmental Quality, said Philip Ralston, the port's director of environmental operations.
The chief concern is that the groundwater contamination might migrate east of the airport, where Portland Water Bureau operates wells that serve as the region's main backup water supply to the Bull Run Reservoir.
But early testing shows the contamination, so far, appears confined to within a few hundred feet of the airport's fire training pits, which are west of the airport, between a runway and the Columbia River.
"The data tell us we seem to have a localized problem," said Dan Hafley, a DEQ hydrogeologist and project manager. "Within a few hundred feet, we're not seeing contamination."
"Right now, we know our drinking water has not been impacted," Ralston said.
There's no sign yet that the contamination has reached the Columbia River, though groundwater tends to flow in that direction, Hafley said.
"I'm less concerned about the groundwater, certainly, than I was before," he said.
But PFOS and PFOA have been officially labeled as "contaminants of emerging concern," and are drawing increasing attention from scientists and regulators as potential threats to human health, wildlife and the environment.
Lab experiments with animals found the two compounds can damage livers, impact the immune system, and cause developmental delays.
Last year, the U.S. Environmental Protection Agency set a "health advisory level" of a miniscule 70 parts per trillion for PFOS and PFOA, combined, in the drinking water supply. Anything above that could be a health concern.
"This is an emerging issue around the world," Ralston said.
The next PCB problem?
Some scientists compare the two compounds to PCBs, the main "contaminant of concern" in the Portland Harbor Superfund site on the Willamette River, which is expected to require a $1 billion cleanup.
Like PCBs, they are persistent "legacy" chemicals found everywhere long after they were phased out of use.
"They don't break down once they get in the environment," Ralston said. "It's really difficult to treat or remediate this stuff in soil and water."
PFOS and PFOA also have been used in the semiconductor and other industries, and in consumer products, such as food wrappings and Goretex clothing, scientists say. They have been detected in leachate leaking from landfills, in sewage treatment plants, and in pretty much every human's blood.
So far, the Port of Portland has spent roughly $125,000 on its investigation, but is bracing for much more.
"I think we're going to be dealing with this for a number of years going forward," Ralston said.
Required by FAA
Fighting fires at airports, where there are high volumes of fuel that can lead to extremely hot fires, requires special training and firefighting foams tailored for such conditions.
"The concern is, for a large aircraft fire, you really got to go in there and knock it down fast," Ralston said.
Fires are actually quite rare at Portland International Airport. Steve Johnson, the port's manager of content and media relations, said he only recalls one fire during his 18 years working at the airport.
But since the 1960s, the Federal Aviation Administration has required ongoing firefighter training using the special foams.
Firefighters routinely trained for such emergencies four or five times a year, at training pits about a half-mile west of the main airport complex, Ralston said.
According to the DEQ, an estimated 24,000 gallons of fuel a year were ignited at the first two pits from 1963 to 1989, with foams containing PFOS and PFOA used to extinguish the fires. Those were bare pits where the chemicals could seep into the soil. Later a third pit was created and lined, to limit contamination.
The port has no solid estimate on how much foam was used.
The firefighting foams were not used in the Troutdale and Hillsboro airports, where the aircraft are typically much smaller.
As more data emerged about hazards from the compounds, the primary manufacturer, 3M Company, stopped making foams with PFOS about 16 years ago and stopped making foams with PFOA about two years ago, Ralston said.
The substitute materials used in present-day foams are fairly similar chemically, but there's less research about those, he said.
"My understanding is that they're less toxic," Hafley said.
To minimize contamination, Portland International Airport has cut its firefighter training down to about one exercise a year.
Air base contaminated
The U.S. Air Force started looking into the foam problem a year and a half ago, and DEQ learned there is contamination at the Oregon Air National Guard base just south of the main airport, Hafley said.
The Air National Guard, which conducts its own firefighter training, signed a voluntary cleanup agreement with DEQ.
The state environmental regulator alerted the Port of Portland about the problem in September 2016, and the port moved quickly to sign a voluntary cleanup agreement in January, Hafley said.
The Air National Guard is moving slower, but will launch its first study next spring, he said.
The Port of Portland is finishing up work on its second study at the airport, as it tries to delineate boundaries for how far and how deep the contamination extends. A test well was dug closer to the main airport complex about a half-mile east of the training pits, and didn't find any of the two contaminants, Ralston said.
The city's water well field starts more than a mile east of that, beyond 82nd Avenue.