With Shell's Kulluk drilling vessel pulled off the rocks and towed to shelter in Alaska, more details are emerging about the rig's grounding in bad weather.

Rachel Maddow addressed the oil company's mishap this week, saying, "the engineering aspects of this story started off really weird" and the story is "getting weirder and weirder all the time" as more information about Shell's original motives for attempting to tow the rig back to Seattle become clearer.

Rep. Ed Markey (D-Mass.) sent a letter to Shell President Marvin Odum this week, suggesting that the company's attempt to move the Kulluk "may have been driven, in part, by a desire to avoid … tax liability on the rig" and not because of weather concerns.

The top Democrat on the House Natural Resources Commitee wrote, “Reports that financial considerations rather than safety may have factored into Shell’s considerations, if true, are profoundly troubling."

Had Shell left the vessel in Alaskan water beyond January 1, 2013, the company would have been liable for a $6 million tax.

Shell claimed that a "two-week window of good weather" prompted the decision to move the Kulluk south from Alaska to Washington. Yet, according to Markey's letter, National Weather Service (NWS) marine forecasts for Alaska "extend only for five days" and Shell allegedly ended conference calls with NWS officials on November 15, 2012.

Shell did not respond to MSNBC's requests for comment, Maddow said. Odum said in a statement on Shell's website, “We undertake significant planning and preparation in an effort to ensure these types of incidents do not occur. We’re very sorry it did. Since the grounding, Shell has worked with all parties in the Unified Command structure to ensure a safe outcome and to protect the maritime environment in the vicinity of the grounded vessel."

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  • This image provided by the U.S. Coast Guard shows the Royal Dutch Shell drilling rig Kulluk aground off a small island near Kodiak Island Tuesday Jan. 1, 2013. A Coast Guard C-130 plane and a helicopter were used to fly over the grounded vessel on Tuesday morning. The severe weather did not permit putting the marine experts on board the drilling rig, which is near shore and being pounded by stormy seas. (AP Photo/U.S. Coast Guard)

  • This aerial image provided by the U.S. Coast Guard shows the Royal Dutch Shell drilling rig Kulluk aground off a small island near Kodiak Island Tuesday Jan. 1, 2013. No leak has been seen from the drilling ship that grounded off the island during a storm, officials said Wednesday, as opponents criticized the growing race to explore the Arctic for energy resources. (AP Photo/U.S. Coast Guard)

  • This aerial image provided by the U.S. Coast Guard shows Rear Adm. Thomas Ostebo, Incident Management Team commander, observing the Royal Dutch Shell drilling rig Kulluk aground during an overflight off a small island near Kodiak Island Tuesday Jan. 1, 2013. No leak has been seen from the drilling ship that grounded off the island during a storm, officials said Wednesday, as opponents criticized the growing race to explore the Arctic for energy resources. (AP Photo/U.S. Coast Guard, Sara Francis)

  • A salvage team moves an emergency towing system across the deck of petroleum drilling ship Kulluk in this photo made Wednesday, Jan. 2, 2013, and provided by the U.S. Coast Guard. There's no indication of a fuel leak from Kulluk, the Coast Guard said Wednesday night, Jan. 2, 2013, of a maritime accident that has refueled debate over oil exploration in the U.S. Arctic Ocean. (AP Photo/U.S. Coast Guard)

  • A photo provided by the U.S. Coast Guard shows a salvage team wrapping up lines from an emergency towing system delivered to the deck of the petroleum drilling ship Kulluk Wednesday, Jan. 2, 2013, in the Gulf of Alaska. The grounding of the drill ship on a remote Alaska island has refueled the debate over oil exploration in the U.S. Arctic Ocean. (AP Photo/U.S. Coast Guard)

  • In this photo provided by the United States Coast Guard, the tugs Aiviq and Nanuq tow the mobile drilling unit Kulluk while a Coast Guard helicopter from Air Station Kodiak transports crew members on Saturday, Dec. 29, 2012, 80 miles southwest of Kodiak City, Alaska. The tug lost the initial tow Thursday and suffered several engine failures prompting the deployment of response assets by the Coast Guard and Royal Dutch Shell. (AP Photo/United States Coast Guard, Petty Officer 1st Class Sara Francis)

  • In this photo provided by the United States Coast Guard, crew members of the mobile drilling unit Kulluk arrive at Air Station Kodiak after being airlifted by a Coast Guard helicopter crew from a vessel 80 miles southwest of Kodiak, Alaska on Saturday, Dec. 29, 2012. A total of 18 crew members of the mobile drilling unit were airlifted to safety after they suffered issues and setbacks with the tug and tow. (AP Photo/United States Coast Guard, Petty Officer 3rd Class Jonathan Klingenberg)

  • In this photo provided by the United States Coast Guard, a Coast Guard helicopter crew from Air Station Kodiak conducts the 13th hoist of 18 crewmen from the mobile drilling unit Kulluk on Saturday, Dec. 29, 2012, 80 miles southwest of Kodiak City, Alaska. The tug Aiviq suffered problems towing the Kulluk Thursday prompting the Coast Guard to deploy cutters and aircraft to while Royal Dutch Shell dispatched additional tugs.(AP Photo/United States Coast Guard, Petty Officer 1st Class Sara Francis)

  • In this photo provided by the U.S. Coast Guard, the tug Aiviq travels at just under 2 mph with the mobile drilling unit Kulluk in tow 116 miles southwest of Kodiak City, Alaska, Sunday, Dec. 30, 2012. The crews remain stationed with the drill rig Kulluk Sunday 20 miles from Alaska's Kodiak Island as they wait in rough seas for another tug boat to arrive. The Coast Guard says the goal is to tow the Kulluk to a safe harbor and determine the next step. (AP Photo/U.S Coast Guard, Chris Usher)

  • In this photo provided by the U.S. Coast Guard, the mobile drilling unit Kulluk is towed by the tugs Aiviq and Nanuq in 29 mph winds and 20-foot seas 116 miles southwest of Kodiak City, Alaska, Sunday, Dec. 30, 2012. The crews remain stationed with the drill rig Kulluk Sunday 20 miles from Alaska's Kodiak Island as they wait in rough seas for another tug boat to arrive. The Coast Guard says the goal is to tow the Kulluk to a safe harbor and determine the next step. (AP Photo/U.S Coast Guard, Chris Usher)

  • Shell-Arctic Drill Ship

    Shell Oil incident commander Susan Childs, second from right, answers a question about the Monday night grounding of the Shell drill ship Kulluk at a press conference on Monday, Dec. 31, 2012, at the Mariott Hotel in Anchorage, Alaska. Looking on are Shell Alaska spokesman Curtis Smith, standing, Coast Guard Commander Shane Montoya, state on-scene coordinator Alan Wien, and Garth Pulkkinen of Noble Corp., the operator of the Kulluk. The drifting Shell drill ship that broke loose from tow vessels during a severe Gulf of Alaska storm ran aground Monday in shallow water off Sitkalidak Island, company officials said. (AP Photo/Dan Joling)

  • In this image provided by the U.S. Coast Guard shows two life rafts sit on the beach adjacent as the conical drilling unit Kulluk sits grounded 40 miles southwest of Kodiak City, Thursday, Jan. 3, 2012. The Kulluk grounded after many efforts by tug vessel crews and Coast Guard crews to move the vessel to safe harbor during a winter storm.Calls for federal scrutiny of Royal Dutch Shell PLC drilling operations in Arctic waters swelled Thursday with a request for a formal investigation by members of Congress. (AP Photo/U.S. Coast Guard, Petty Officer 2nd Class Zachary Painter)

  • Royal Dutch Shell PLC incident commander Sean Churchfield briefs reporters on the status of salvage operations for the Shell drill ship Kulluk at a news conference in the Denaíina Civic and Convention Center on Thursday, Jan. 3, 2012, in Anchorage, Alaska. The drill ship ran aground on Monday, Dec. 31, off Sitkalidak Island near Kodiak Island in the Gulf of Alaska. (AP Photo/Dan Joling)

  • In this image provided by the U.S. Coast Guard the conical drilling unit Kulluk sits grounded 40 miles southwest of Kodiak City, Thursday, Jan. 3, 2012. The Kulluk grounded after many efforts by tug vessel crews and Coast Guard crews to move the vessel to safe harbor during a winter storm.Calls for federal scrutiny of Royal Dutch Shell PLC drilling operations in Arctic waters swelled Thursday with a request for a formal investigation by members of Congress. (AP Photo/U.S. Coast Guard, Petty Officer 2nd Class Zachary Painter)

  • Coast Guard Capt. Paul Mehler briefs reporters on the status of salvage operations for the Shell drill ship Kulluk at a press conference in the Dena'ina Civic and Convention Center on Thursday, Jan. 3, 2012, in Anchorage, Alaska. The drill ship ran aground on Monday, Dec. 31, off Sitkalidak Island near Kodiak Island in the Gulf of Alaska. (AP Photo/Dan Joling)

  • This aerial image provided by the U.S. Coast Guard shows the Royal Dutch Shell drilling rig Kulluk aground off a small island near Kodiak Island Tuesday, Jan. 1, 2013. No leak has been seen from the drilling ship that grounded off the island during a storm, officials said, as opponents criticized the growing race to explore the Arctic for energy resources. (AP Photo/U.S. Coast Guard)