Beloved Alaska disc golf course was built around bubbling crude oil from a sealed-off tank area

In Juneau, Alaska, a popular public park is showing how contamination from long-closed industry can remain hidden for decades before reappearing in ordinary community spaces.

Visitors to the historic Treadwell Mine complex on Douglas Island now pass trails and a nine-hole disc golf course alongside a sealed-off former tank area, where crude oil has started rising to the surface.

What happened?

A bright orange plastic fence now cordons off part of the Treadwell Mine ruins after thick oil was found surfacing near one of the park's popular trails.

As KTOO reported, a local resident said there was an oil sheen at the site in August 2025.

Marc Wheeler, director of parks and recreation for the City and Borough of Juneau, said, "It seemed to have made its way to the surface last summer."

Wheeler also said the substance appears to be especially heavy.

"They used bunker fuel, so it's similar to what the cruise ships use," he said. "It's a very dense kind of tar-like fuel source."

The oil is believed to be coming from an old tank known as Day Oil Tank Number 8, which Paulette Simpson, president of the Treadwell Historical Society, said may once have held 10,000 gallons of crude oil.

Why does it matter?

The Alaska Treadwell Mining Company went under after a huge cave-in in 1917, long before laws required companies to pay for cleanup or reclamation.

Those mining remnants were later incorporated into a city park with a disc golf course, and state officials are trying to find out whether contamination has moved outside the old tank ring.

To start that work, the state secured a $25,000 grant from the U.S. Environmental Protection Agency for sampling planned this summer.

Flannery Ballard, an environmental program specialist with the program, said the first questions are straightforward but critical. "One of the things we're going to investigate with our initial sampling is just, has contamination made out of the ring?" she said. "If it has, how far widespread is it? How deep does it go?"

Public funds may now be needed to investigate and eventually clean up pollution left behind by a long-defunct private company.

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