On September 6, 1999, the Stuyvesant spilled at least 2100 gallons of Intermediate Fuel Oil 180 (IFO-180) into the Pacific Ocean near the mouth of Humboldt Bay, near Eureka, California. The incident began at approximately 5:00 pm at least one nautical mile offshore from the channel into Humboldt Bay. A dredge arm on the Stuyvesant punctured one of its fuel tanks. At that time, however, the puncture was below the water line and pressure from the ocean water may have limited the release of oil. The dredge proceeded to a point approximately four miles off the North Spit where it dumped its dredge spoils. At this time, 6:54 pm, the vessel became much lighter, the puncture in the fuel tank rose above the water line, and the oil leak may have begun in earnest. The vessel proceeded to return to Humboldt Bay and was inside the channel between the North and South Spits at approximately 7:30 pm. An out-going tide prevented oil from entering Humboldt Bay.

At this point, the vessel turned around and headed back out to sea. By 8:22 pm, the Stuyvesant was approximately three miles offshore, directly out from the channel entrance. At this time, oil was moved to other compartments in the vessel in an effort to stem the leak. At 11:30 pm, the vessel moved further offshore. By 4:10 am on September 7, the Stuyvesant was approximately 15 miles offshore and the leak was stopped. It appeared that most of the escaped oil was released within four miles of the coastline.

Strong north winds (17 knots at the Eel River Buoy) initially spread oil to the south. However, these were replaced with south winds (15 knots) by the afternoon of September 7. Strong south winds prevailed for most of the ensuing days, causing the oil to spread primarily to the north. Overflights by National Oceanic and Atmospheric Administration (NOAA) identified oil slicks and tarballs in the ocean as far as 15 miles offshore and as far north as Patrick’s Point.