Diesel fuel has been slowly leaking into the water near the Hyde Street Pier for months, prompting an ongoing cleanup effort that's removed 449 gallons of fuel from the bay.
The California Fish and Wildlife Department's Office of Spill Prevention and Response has been working with the Coast Guard to clean up the spill, first reported by the Port of San Francisco on July 9.
The spill site is immediately adjacent to the historic Hyde Street Pier, whose ferries were the only way to access Marin County or Oakland before the construction of the Bay and Golden Gate bridges. The pier now falls partly under the jurisdiction of the National Park Service.
The fuel appears to be seeping out from behind 300 feet of stone bulkhead, just steps from the busy pedestrian paths of Fisherman's Wharf and a short distance from the hundreds of sea lions that famously call the area home.
Eric Laughlin, a public information officer for Fish and Wildlife, says its source remains unknown.
"Since the early 1900s, several oil companies have either stored or handled petroleum products in this area," Laughlin said. "There's just so many potential sources. It might even be a pipeline."
The site, like most of San Francisco's waterfront, has a complicated past. Formerly known as Wharf J10, it handled machinery and fuel for over a century, before 1972's Clean Water Act made sweeping reforms to the industrial abuse of marine areas.
Those reforms were a boon to a bay now recognized as a critical, delicate ecosystem, after decades of heavy misuse by the mining and shipping industries. In addition to the sea lions, the San Francisco Bay is a migratory stop for whales, millions of birds and two-thirds of the state's salmon population.
Asked how the spill could impact the surrounding marine life, a representative for the Marine Mammal Center said it was the first they'd heard of it, and that they would need more information to make a determination.
One of the key components of the Clean Water Act was the "polluter pays" principle, which makes it possible to hold corporations financially accountable for their past behavior.
Wharf J10 was already the source of a spill and cleanup that started in 2008, and was declared clean in 2016. Laughlin said the spill was attributed to a century-old company now owned by Exxon Mobil, using a "fingerprinting" process that determines a petroleum's source.
"In 1913, General Petroleum and Mobil operated a fuel storage facility at that exact site," Laughlin explained. The companies are now owned by Exxon.
After testing the current spill, Fish and Wildlife has determined that the fuel is from an entirely different manufacturer. "You would think that this is Exxon, too, but it's not," Laughlin said.
Attributing the source of the spill is critical, because it determines who will ultimately be sent the bill for cleanup — which can run to the tens of millions of dollars.
Until the source of the leak can be found, OSPR and the Coast Guard will continue doing cleanup with an oil skimmer and absorbent booms (pictured above), which soak polluted water out of the harbor.
"We're going to work to get it cleaned up, and then figure out who's responsible," Laughlin said. But for now, there's no end in sight.