PAULSBORO — Citgo does not have to pay $177 million in cleanup costs stemming from the massive 2004 spill of crude oil from a tanker nearing its dock on the Delaware River, a federal judge has ruled.

The judge cleared Citgo of liability in the third-largest oil spill in U.S. waters, which occurred when the single-hull Greek tanker struck a rusty anchor long submerged in the riverbed.

Nearly 265,000 barrels of heavy crude oil gushed out as the tanker neared the Citgo dock in Paulsboro, N.J., near Philadelphia, after a six-day journey from Venezuela. The spill hampered shipping and polluted more than 45 miles of shoreline in New Jersey, Pennsylvania and Delaware.

At the time, it ranked as the second-worst oil spill in U.S. waters. The total bill for the cleanup topped $267 million.

The lawsuit involved efforts by the U.S. government and Frescati Shipping Co., which owned the Athos I, to try to recover their costs from Citgo. Frescati sought about $90 million and the U.S. government $87 million. Frescati argued in part that Citgo had a duty to maintain the area around its dock.

However, Senior U.S. Judge John P. Fullam rejected their claims, blaming the spill on the person who abandoned the anchor. That person's identity remains unknown because the portion of the anchor that contains identifying marks was broken off.

"There is no evidence that any party to this litigation — Frescati, (Citgo) or the government — knew or had reason to believe that the anchor was in the river, although it is well-known that all sorts of objects that present a potential danger to navigation lurk beneath the surface of the waters," Fullam wrote Tuesday.

The Athos I had traveled 1,900 miles after picking up its Venezuelan crude and was 900 feet from the Citgo asphalt refinery's dock on Nov. 26, 2004, when it started to list. Evidence at the 41-day bench trial showed the anchor had been submerged in approximately the same spot since at least 2001, when it appeared in a scan of the riverbed.

Fullam said Citgo had no responsibility to maintain the site, which was in a busy public waterway.

"Although the docking pilot was aboard the Athos I, the ship was in an area of the anchorage open for the passage of all ships, not an area used exclusively, or even primarily, by vessels docking at the Paulsboro refinery," Fullam wrote.

Rich Whelan, a lead lawyer for Citgo, said the ruling confirms that marine terminal operators are not liable for the maintenance of public waterways.

"We think it's an important decision for marine terminal operators, because the judge limited their responsibility to the immediate berth or dock area, and refused to extend the responsibility into public waters," Whelan told The Associated Press.

A lawyer representing the shipping company in the case did not immediately return a message late today.

Under laws in place at the time, the ship owner's liability for the cleanup was limited to $45 million.

Frescati, in its lawsuit, said it paid $35 million in related interest and $10 million in accident-related damages, for the $90 million total.

The Coast Guard assumed much of the additional cost. The Justice Department, whose maritime lawyers pursued the government claims at trial, did not immediately return a call for comment.

At the time, the Delaware River spill ranked as the second worst in U.S. waters, after the Exxon Valdez spill in Alaska in 1989. The Deepwater Horizon disaster in the Gulf of Mexico last summer has since surpassed it.

In its wake, Congress passed a law in 2006 designed to encourage the use of double-hull tankers by tripling fines for single-hull vessels. Proponents of the bill said that 19 of the 20 largest U.S. oil spills from 1990 through 2006 were from ships without double-hulls.

The law, the Coast Guard and Maritime Transportation Act of 2006, also requires anyone with knowledge of possible river obstructions to report that to the Coast Guard and Army Corps of Engineers.

Numerous government agencies responded to the spill, with mixed success, given the damage to wildlife and the environment in the three-state area.

"The testimony of the witnesses was compelling with regard to the complexity and difficulty of the oil spill response, and that costs were monitored to the best extent possible under the circumstances," Fullam wrote.

Related coverage:

• $20M to help Delaware Bay after oil spill

• $8.125M to settle Citgo tax case

• CITGO agrees to sell asphalt refineries