Cause of Coralville treatment plant explosion still unclear

It looks like methane is the culprit, but authorities still aren't exactly sure what led to an explosion at Coralville's wastewater treatment complex Monday that injured a man.

Fire Chief Dave Stannard said methane buildup was the “only possibility” for the explosion but authorities are not sure why it built up or where.

“We haven't determined exactly whether there was a system malfunction or breakdown,” he said. “That's still under investigation.”

The person injured was Brian Lamansky, the city's wastewater superintendent, City Manager Kelly Hayworth said.

Stannard didn't know the full extent of Lamansky's injuries but said they include a broken leg that will require pins to be inserted in it. He is in a lot of pain, but the injuries are not life-threatening and he should recover, Stannard said. He is being treated at University of Iowa Hospitals and Clinics.

The explosion occurred just after 11 a.m. Monday and was felt several miles away.

Stannard said Lamansky was working on the roof of the sludge-storage facility at the wastewater treatment plant, 750 22

^nd

Ave.

The 1.5 million-gallon tank holds solid waste, or sludge, that has been removed during the treatment process. Lamansky was working in conjunction with an outside contractor, who was not in the area at the time of the accident, to prepare for the removal of the sludge.

Once a year, the sludge is taken from the tank and applied to farmland, Stannard said. It's believed Lamansky was using a torch to try to open a frozen hatch on the roof of the facility. That's when the explosion occurred.

Stannard said he wasn't sure if there are safety protocols to be followed for such work. He did say, however, that Lamansky was in an area that would not normally be considered hazardous. The sludge-storage facility has 12 ventilation ports to let methane escape and has never had problems before, he said.

“It's a pretty simple facility,” Stannard said. “It's not very complicated. So we wouldn't normally consider it a high-risk thing.”

Methane is a colorless, odorless, flammable gas.

Hayworth said he's seen no evidence safety precautions weren't followed. Crews use meters to measure gases in enclosed spaces, but they wouldn't typically expect to encounter gas outside, he said.

Lamansky has more than 30 years experience, Hayworth said.

The Iowa Department of Natural Resources regulates the treatment process and discharge at municipal wastewater plants but does not conduct safety inspections, said Dennis Ostwinkle, supervisor of the DNR's Washington field office, which covers Johnson County.

The Coralville plant has not had any discharge violations over the past three years, he said.

No sludge was released in the explosion, so there is no environmental concern, Ostwinkle said.

Stannard said the sludge will need to be removed from the tank before the extent of the damage to the facility is known. There is no cost estimate for the damage at this time.

The city is evaluating what to do with the waste in the tank and then will figure out how to fix the facility, Stannard said. The city's ability to process wastewater has not been affected, he said.