NILES - Crews remained along a stretch of the Mahoning River most of Monday, looking for any lingering pockets of oil from Friday's spill.
Ohio Environment Protection Agency officials said it appears between 400 and 500 gallons of oil made its way along 4 to 4 1/2 miles of the Mahoning River, beginning near the former RG Steel plant and moving downstream.
OEPA officials said they do not expect fines to be levied against the Warren Township company connected to the discharge.
Ron Vlasaty, project manager with EnviroServe of Cleveland, describes Monday how the oil is contained by four, 250-foot booms that span the Mahoning River at the Belmont Avenue bridge in Niles.
Tribune Chronicle / R. Michael Semple
Workers placed in the river about 1,000 feet of boom, which is used to contain the oil and stop it from from migrating downstream, under the Belmont Avenue bridge in Niles.
"People have been out on boats working, breaking up debris," explained Mike Settles, OEPA spokesman. "We know that there hasn't been any release or discharge of oil since Friday so the focus over the weekend and now has been on the cleanup effort."
A "very light sheen" of oil continued moving down river Monday afternoon but efforts to stop it at the boom have been successful, Settles added.
Settles said that because the oil is light, it spills and dissipates quickly.
The spill was reported to the Niles Fire Department about 1:30 p.m. Friday by someone on the bike path who noticed a sheen on the river, prompting multiple agencies to kick into action.
Trumbull County Emergency Management Agency and HazMat traced the leak to the ArcelorMittal plant off Main Avenue in Warren Township before OEPA officials arrived.
However, Settles said ArcelorMittal was already aware that waste water from a pond had overflowed and that the company had started that cleanup effort earlier on Friday.
"It could have been that the rain caused the pond to overflow and jump its banks," Settles said.
He confirmed there were actually two separate problems - the overflowing pond and a malfunctioning oil polishing system - that contributed to oil being discharged.
On Monday, ArcelorMittal officials said they are taking the matter "very seriously" and have been working cooperatively with the agencies involved to address it.
In a written statement, the company confirmed it was notified on Friday "of an observed oil presence on the Mahoning River" and that "the company immediately conducted an inspection of all areas of the facility and identified and addressed the source of the release."
Settles also said ArcelorMittal has been cooperating with OEPA and at this point he does not foresee that the company will be fined.
He said OEPA officials will continue to evaluate the situation to determine whether there has been any environmental impact. He said OEPA will also continue to monitor the company's operations to make sure its permits are in order and that it is complying with regulations.
"At this point we haven't seen any evidence of impact on the wildlife in the area," he said. "And ArcelorMittal has been right on board, cooperating every step of the way."
He said it's still too soon to determine the cost of the cleanup.
Jason DeLuca of Trumbull County HazMat said officials will have more answers as they get into the "wrap-up phase" of the cleanup effort.
He said that as of Monday, it appeared the cleanup was effective and that crews were making steady progress.
Private companies are doing most of the cleanup.