The reported leakage of diesel fuel in the downtown sewer system late last week and into this week appears to have subsided and a potential source has been identified, city and state officials said Thursday afternoon.

“There’s a high probability that the problem is solved,” said Denise Koch, deputy director of the City and Borough of Juneau’s Engineering and Public Works Department.

Late last week Koch said the employees with CBJ Water Utilities Division noticed the smell of diesel in the downtown area and at the Juneau-Douglas Wastewater Treatment Facility. She said the city also received multiple reports from local downtown businesses that noticed a similar diesel smell.

Koch said CBJ partnered with the Alaska Department of Environmental Conservation Prevention, Preparedness and Response officials to investigate the situation and look for a potential source. However, no clear source was able to be identified Wednesday. The city then shared a public notice on its website and social media on Wednesday evening to seek information from residents who may know the source of the leak.

Koch said the idea behind the PSA was to seek information, but also to encourage residents and businesses to check their tanks for possible leakage. It seemed to have worked, as on Thursday, Koch said the smell of diesel has subsided at the waste treatment facility and they believe the potential spill has been stopped. According to Rachael Krajewski, Southeast region environmental programs manager for DEC, late Thursday afternoon a potentially responsible party self-reported following the PSA and is working with the department.

“Our PSA was successful and achieved what we wanted it to achieve — which is that we have no indication of diesel in our sewer system or at the wastewater treatment plant — so that is really good news,” Koch said. “We’ve been monitoring and so far as I mentioned, we’re not smelling it.”

Koch said CBJ does not know the amount of diesel that may have been spilled and it would be difficult to identify that. She said regardless of the quantity, diesel can have devastating negative impacts on the treatment plant and the environment if leaked. Diesel can also pose significant risks to human health and infrastructure.

Koch also noted that the outfall from the Juneau-Douglas Wastewater Treatment Facility goes into the Gastineau Channel, which could also be negatively impacted by diesel leakage.

“Our treatment plant is a biological treatment system, so we have microorganisms that break down our waste products from the sewer — petroleum is not good for them,” she said. “You don’t want it in the system because it can also change the pH which is also not good for the microorganisms.”

• Contact reporter Clarise Larson at clarise.larson@juneauempire.com or (651) 528-1807.