Although initial reports downplayed the significance of Thursday's oil spill from The Dalles Dam, the visual evidence suggested a much bigger problem.
The oil spill caused a slick that was carried west and was clearly visible in the Columbia River as far as Bingen by Friday. By 3 a.m. on Saturday, the oil had reached the Bonneville Dam.
The spill, discovered at 8 a.m. on Jan. 15, was apparently caused by broken cooling water pipes on an electrical transformer. It first leaked onto the transformer deck and then into the building, where some of the oil escaped to the river.
"We identified the spill at 8 a.m. on the 15th," explained Matt Rabe, public affairs specialist with the U.S. Army Corps of Engineers in Portland. "Corps maintenance crews went to work immediately to capture oil behind the dam as well as to arrest the leak. The cleanup contractor was on scene that afternoon."
Army Corps of Engineers officials believe the break was caused by recent freezing weather conditions in the Columbia River Gorge.
On Monday, Rabe said there was no certain estimate yet on how many gallons of oil were released.
"We're comparing maintenance records with the amount of oil that should be in there versus the amount withdrawn from the transformers, and comparing that with the amount cleaned up," Rabe said.
Rabe added that he believes the maximum the spill could be was 5,000 gallons, but he expects it to be smaller.
"I see that number coming down. How far down, I don't know," he said.
Officials at the dam first estimated that about 75 gallons of oil discharged into the river. The Corps of Engineers contacted NRC Environmental (formerly known as Foss Environmental) to spearhead the cleanup effort. NRC is headquartered in Seattle, but the team that responded to the incident at The Dalles was based in Portland.
NRC was using vacuum pumps, skimmers, absorbent material, and booms to recover oil from the river.
By Sunday, crews reported recovering more than 600 gallons of oil, and said more than 4,000 feet of boom had been deployed at the mouths of creeks and streams to capture residual oil.
Rabe conceded that the initial reports on the spill did not reflect the potential seriousness of the situation.
"We've been criticized for the `75 gallons,' but that was an early estimate based on visual inspection," Rabe explained. "As anybody knows with an event like this, numbers change quickly. We know it's larger than 75 gallons. We don't know where it will sit ultimately, but we're committed to removing as much oil as possible."
A representative of Columbia Riverkeeper (CRK), a Gorge-based environmental advocate, blasted what he characterized as the Corps' inadequate response to the spill.
"The event occurred at 8 a.m. Thursday, and many hours passed with nothing being done," said CRK's Greg deBruler. "Then they said 185 shad were killed. Only shad? This is the only fish in the river?"
DeBruler also disputed the initial reports of how much oil got into the river. He said he crossed the Hood River Toll Bridge on Friday afternoon, and saw bands of oil across the whole width of the river.
"It was sure not 75 gallons. I think it's at least hundreds of gallons. It's not an Exxon Valdez, but the real problem is the Corps did not respond properly," deBruler explained. "There were no emergency crews stationed at the dam. Every dam should have a spill response team on hand. No more of this sloppy behavior by the Corps. We want full accounting and notification immediately. There were fishermen out on the river, sitting in pools of oil."
Rabe disputed CRK's characterization of the Corps' response.
"I would say we have an up-to-date spill response plan at our facilities," Rabe said. "Our maintenance team is trained to contain any spill that reaches the river, and we have an ongoing relationship with NRC. We contacted them immediately to assist. We take these matters very seriously and took immediate steps to notify the proper authorities and contain the spill. We feel we've been aggressive in identifying the problem and getting it remedied."
The transformers, which can hold as much as 18,000 gallons of oil, are located on the roof of the powerhouse and are exposed to outside weather.
Workers drained more than 7,000 gallons of oil from the transformer after the leak, but it remained unclear how much had been in the transformer when it began leaking. The transformer had been partially drained earlier in the winter.
The oil involved was described by the Corps of Engineers as "a light-grade mineral oil, used as a coolant within the transformer."
The oil had been contaminated with polychlorinated biphenyls (PCBs) in a reported concentration of eight parts per million -- a level the U.S. Environmental Protection Agency considers to be "non-hazardous." State and local health officials said they believe risk of exposure to the public is extremely low.
DeBruler pointed out that there is a pool at The Dalles Dam that is prime habitat for sturgeon.
"The oil takes several days to break down, then the PCBs fall out. There could be damage to the food chain," he explained. "The PCBs are carcinogenic and can cause genetic damage."
There were no immediate reports of oiled birds, but residents were advised to call 1-800-22-BIRDS to report sightings of impacted wildlife.
"We continue to be on the lookout for injured or oiled wildlife. We've found nothing so far," Rabe said Monday.
The Corps reported the incident to the National Response Center, the Oregon Emergency Management Office, and the Washington Department of Ecology (WDOE) as soon as it was determined that the oil was discharged to the river.
"We are doing everything we can to aggressively and effectively respond to this spill," said Mark Layman of the WDOE.
The Dalles Dam, in operation since 1957, spans the Columbia River 86 miles east of Portland.