Shell may have moved troubled Alaskan rig to avoid $6 million tax, congressman says

Jan. 2: Royal Dutch Shell drilling rig Kulluk aground off a small island near Kodiak Island

Jan. 2: Royal Dutch Shell drilling rig Kulluk aground off a small island near Kodiak Island  (U.S. Coast Guard/AP)

Royal Dutch Shell may have moved an oil rig that ran aground last month in order to avoid $6 million in taxes to Alaska, Rep. Ed Markey, D-Mass., charged in a letter to the oil behemoth's president.

Markey, a member of the House Natural Resources Committee and an outspoken critic of BP after the 2010 Gulf Coast oil spill, said in the letter that Shell officials made statements that "may have been driven, in part, by a desire to avoid tax liability on the rig."

The oil drill, which had no engines of its own, was being towed for maintenance when it ran aground on a remote Alaska island during a powerful storm on New Year's Eve. It was carrying more than 140,000 gallons of diesel and about 12,000 gallons of lube oil and hydraulic fluid.

The oil drill was eventually freed from the rocks and moved to a nearby harbor.

Alaska's 2 percent drilling equipment tax is levied on rigs within its borders as of Jan. 1, according to a Reuters report. Shell has maintained that the decision to move the Kulluk drill rig from Dutch Harbor to Seattle on Dec. 21, was due to forecasts of good weather for two weeks in the Gulf of Alaska.

Curtis Smith, a Shell spokesman, told The Alaska Dispatch earlier this month that the "two-week window of good weather" was what mattered most to the company.

Although the oil giant employs its own meteorologists, Markey's letter claims that the National Weather Service in Alaska does not make marine forecasts that far into the future.

Susan Buchanan, a spokeswoman for the National Weather Service, told FoxNews.com that the agency does not make marine weather forecasts beyond seven days.

Shell did not return a phone call from FoxNews.com, but a spokeswoman responded to Markey's letter to Reuters and said the plan was always to move the Kulluk in December.

"While we are aware of the tax environment wherever we operate, the driver for operational decisions is governed by safety,” she told the news agency.

Shell has invested billions of dollars gearing up for drilling in the Beaufort and the Chukchi seas, off Alaska's north and northwest coast.

The potential bounty is high: The U.S. Geological Survey estimates 26.6 billion barrels of recoverable oil and 130 trillion cubic feet of natural gas exist below Arctic waters.

Royal Dutch Shell PLC in 2008 spent $2.1 billion on Chukchi Sea leases and estimates it has spent a total of nearly $5 billion on drilling efforts there and in the Beaufort.

The Associated Press contributed to this report

Edmund DeMarche is a news editor for FoxNews.com. Follow him on Twitter @EDeMarche.