Labor unions celebrated after President Trump's nominee to lead the Office of Personnel Management withdrew his name from consideration after more than a dozen unions joined together in opposing his nomination.

George Nesterczuk sent a letter to Trump on Monday requesting that his nomination be withdrawn. Trump in May nominated Nesterczuk to lead OPM, which acts as the government's human resources department, but the White House officially withdrew his nomination Wednesday.

In his letter to Trump, obtained by Government Executive, Nesterczuk cited "partisan attacks" and opposition from federal labor unions as the reasons for his withdrawal.

"I have decided to withdraw because the prospect of my favorable confirmation has grown remote," Nesterczuk said in his letter. "Recent partisan attacks threaten to delay further the consideration of my nomination. These attacks are intended to prevent me, or anyone, from carrying out government reforms that the American people and you, Mr. President, are rightly demanding."

Last month, 16 labor unions sent a letter to Sens. Ron Johnson, R-Wis., and Claire McCaskill, D-Mo., the chairman and ranking member of the Senate Homeland Security and Government Affairs Committee, opposing Nesterczuk's nomination.

In their letter, the unions cited his involvement in the National Security Personnel System, a personnel system created for the Department of Defense in 2003 and repealed by Congress in 2009, as one reason they should reject his nomination.

The unions also urged the senators to oppose Nesterczuk's nomination because of his work advising Ukrainian government officials.

"It is our view that Mr. Nesterczuk's long employment track record both in and out of government as well as for the Ukraine, leave us countless concerns," the unions wrote.

Though Nesterczuk didn't specially reference the claims raised by the unions in his letter to Trump, he said the current environment surrounding all the president's nominees leave him to believe that his nomination would face significant delays.

"While the allegations against me are baseless and false, in the current climate when even non-controversial nominees endure extensive delays in the Senate, I do not wish to be a distraction for the administration while I defend my integrity," Nesterczuk said.

After Nesterczuk's nomination was withdrawn, several unions that signed the letter to Johnson and McCaskill praised the move.

"This is a win for our federal firefighters as George Nesterczuk played a leading role in the creation of the disastrous National Security Personnel System (NSPS), a discriminatory personnel system that did not respect due process worker protections and merit system principals," the International Association of Fire Fighters said on Facebook. "The IAFF made clear our opposition to Nesterczuk's nomination as OPM director. In short, his history as a political appointee of the federal government and his views are in direct conflict with the mission of OPM."

Matt Biggs, legislative and political director of the International Federation of Professional and Technical Engineers, told the Washington Post that Nesterczuk's withdrawal is a "good thing for federal workers."

"Like all agencies, OPM needs a qualified and competent leader who would have the respect and confidence of our nation's federal workers," Biggs said.

The IFPTE organized the letter sent to Johnson and McCaskill.

Randy Erwin, national president of the National Federation of Federal Employees, said the union was pleased with Nesterczuk's decision to remove his name from consideration and accused him of being too political to lead OPM.

"Regardless of the suspicions surrounding his international affairs, Mr. Nesterczuk's previous work on the National Security Personnel System (NSPS) wasted hundreds of millions of taxpayers' dollars implementing and then withdrawing a fatally flawed personnel system," Erwin said. "OPM requires a leader that understands the technical and operational complexities of the federal government. OPM does not need a leader who is ideologically driven nor one who is blind to the importance of an apolitical career federal workforce."