The Coast Guard sent a list of safety and environmental violations to the U.S. Justice Department and the House Natural Resources Committee following an investigation into problems with the Noble Discoverer drill ship.
U.S. Rep. Ed Markey, D-Mass., ranking member of the committee, said he sent a letter to Shell asking what plans it had for drilling in arctic waters given the revelations.
"It is imperative that any drilling operations in the Arctic Ocean occur with the highest levels of safety and environmental protections in place, and I am not convinced that these levels can ever be met given the extreme weather conditions and Shell's performance thus far," Markey wrote.
Markey published a list of 16 violations reported by the Coast Guard. He said there were systematic failures that led to serious engine failures on the Noble Discoverer drillship.
Shell's campaign for exploration off the northern coast of Alaska was hampered by severe weather and a series of equipment malfunctions last year.
In January, U.S. Interior Secretary Ken Salazar ordered a two-month review of Shell's work in Alaska, saying recent missteps may prevent offshore work this year.