A lead congressional committee investigating the Gulf of Mexico oil spill has broadened its inquiry, now checking if tens of thousands of abandoned oil and gas wells are leaking or even being monitored for leaks.
Committee members wrote in a letter Thursday to Interior Secretary Ken Salazar that they were responding to an Associated Press investigation released last week on the 27,000 abandoned wells in the Gulf. The AP reported that the wells are not routinely inspected when plugged or subsequently monitored for leaks.
"These wells could pose an additional danger to the Gulf Coast environment and economy," wrote U.S. Rep. Henry Waxman, D-Calif., chairman of the House Energy and Commerce Committee, and Rep. Edward Markey, D-Mass., who heads the subcommittee on energy and environment. They asked for details on the number of wells as well as leaking and inspection requirements. They asked for an initial reply by Monday.
Some wells have been abandoned in the Gulf since drilling first began in federal waters in the 1940s. Oil companies leave them behind when they are done using them to explore or produce.
Of 50,000 wells ever drilled in the Gulf, 23,500 have been permanently abandoned, the AP reported. Another 3,500 are classified as "temporarily abandoned," but some have been left in that condition since the 1950s without the full safeguards of permanent abandonment.
Petroleum engineers say that even in properly sealed wells, cement plugs can fail over the decades and the metal casing that lines the wells can rust. Even depleted production wells can repressurize over time and spill oil if their seals fail.
BP PLC was temporarily abandoning the Deepwater Horizon well when it blew out on April 20, killing 11 workers.
In response to the AP investigation, leading environmental groups have called for the government to study the possible extent of leaking wells, to conduct work inspections and to monitor abandoned wells over the years.
Sen. Mark Udall, D-Colo., sent a separate letter last week asking Salazar whether regulators have authority to conduct inspections of abandoned wells. He said regulators may ultimately need to check industry paperwork more carefully or inspect the work themselves.
On Thursday, Kendra Barkoff, a spokeswoman for the Interior Department, said the agency was reviewing the latest congressional request. She added that "without question, we must raise the bar for all offshore oil and gas operations."
She gave few details but said the agency is evaluating "a series of options" to make sure that well operators can afford the costs of abandonment. Oil and gas companies eventually will have to spend at least $3 billion to perform permanent plugging on wells in federal waters, according to estimates of the newly named U.S. Bureau of Energy Management, Regulation and Enforcement, which regulates offshore drilling.
In its investigation, the AP found a series of past warnings about the risks at abandoned wells. The Government Accountability Office, which investigates for Congress, warned that leaks could cause an "environmental disaster." The U.S. Environmental Protection Agency has estimated that up to 17 percent of abandoned wells are improperly plugged on land.