For the second time in as many days, Republicans in the Senate blocked committee action to confirm a nominee to President Barack Obama's Cabinet, this time by boycotting a Thursday vote on his pick to head the Environmental Protection Agency.

All eight Republican members of the Committee on Environment and Public Works failed to appear for a vote that would likely have moved nominee Gina McCarthy's selection to the full Senate. The senators said she had refused to answer their questions about transparency in the agency.

The Obama administration expressed outrage, describing the boycott as part of a pattern of Republican obstruction to undermine the president's ability to fill key Cabinet positions.

In the weeks-long hearing on her nomination, McCarthy took more than 1,100 questions. By contrast, the EPA's former administrator under Obama, Lisa Jackson, took 157 questions.