(CBS NEWS) -- President Obama has another cabinet position to fill. Interior Secretary Ken Salazar announced his resignation today and in a letter to his department, he said he plans to leave by the end of March and return to Colorado.
"After much reflection, I have decided to announce that I intend to return to my home state of Colorado and my family, having fulfilled my promise to President Obama to serve four years as Secretary," he wrote to agency staff.
In his letter, Salazar said agency successes include "a renewable energy revolution," land preservation and conservation and the settlement of the Cobell case, a class action lawsuit against the U.S. government by Native Americans.
His tenure also included the BP oil spill in the Gulf of Mexico, which not only spilled about 5 million barrels of oil into the gulf but killed 11 workers. The agency was criticized for the loose permitting process and lax oversight of the oil industry's deep-water drilling.
President Obama released a statement thanking Salazar for his service. "In his work to promote renewable energy projects on our public lands and increase the development of oil and gas production, Ken has ensured that the Department's decisions are driven by the best science and promote the highest safety standards," the president wrote. "Ken has also made historic strides in strengthening our nation to nation relationship with Indian Country, helping to resolve longstanding disputes and make tribal communities safer and stronger."
Salazar was a Democratic senator from Colorado when he was tapped by Mr. Obama to lead the 70,000 employee agency in 2009. With Salazar's departure, both Hispanics that served in the president's first-term cabinet will have stepped down. Hilda Solis announced last week that she won't continue as Labor Secretary in Mr. Obama's second term.