Donald Trump’s pick to head the Central Intelligence Agency (CIA) faces an uphill battle to get Senate confirmation, with many questioning her role in the agency's dark history of torture.
Ms Haspel was picked on Tuesday by President Donald Trump to be the first female head of the CIA.
However, several senators say they want to know more about her time overseeing a secret CIA prison in Thailand from 2003 to 2005 when high-ranking terror suspects were reportedly waterboarded.
She also facilitated the destruction of waterboarding videos.
Although she now serves as CIA deputy director, Ms Haspel has not previously had to undergo Senate confirmation.
John McCain, the veteran Arizona senator, said he wanted to know more about her past roles.
“Ms Haspel needs to explain the nature and extent of her involvement in the CIA's interrogation programme,” Mr McCain said in a statement.
“I know the Senate will do its job in examining Ms. Haspel's record as well as her beliefs about torture and her approach to [the] current law.”
Although the actions had bilateral support when they were introduced after the 9/11 terror attacks, waterboarding was banned in 2006 and enhanced interrogation techniques were further reformed under Barack Obama.
Republicans hope to approve her nomination to replace Mike Pompeo quickly.