The nominations of Gina McCarthy, President Obama's pick to head the Environmental Protection Agency, and Tom Perez, Obama's nominee to serve as the next Labor Dept. secretary, could be in trouble.

Senate committee votes scheduled for May 8 and May 9 were postponed after Republicans on the Committee on Environment and Public Works (EPW) boycotted McCarthy's nomination hearing, and labor committee Republicans used a procedural maneuver to delay the vote on Perez. 

Senate EPW committee Republicans continue to push for a more transparent EPA, particularly around its record-keeping practices. Republicans say that under former EPA Administrator Lisa Jackson, regional administrators used private email accounts to conduct EPA business. They also raise concerns about Jackson's use of an alias email account. Officials at EPA say the alias accounts were a standard practice used by EPA officials during both Republican and Democratic administrations to handle flows of incoming email.

Republicans on the Senate environment committee sent more than 1,000 questions to McCarthy and EPA staff, many of them relating to transparency at the agency. While McCarthy responded to requests about use of government email solely for official business, Republicans say she has not responded to other requests, including queries about how EPA justifies rule-making.

"We're not asking to amend any bedrock environmental laws," said Sen. John Barrasso (R-Wy.) in a statement. "We're asking for access to the scientific data and reasoning behind the justification for expensive new rules and regulations that continue to cause high unemployment."

At the May 9 meeting, Committee Chairman Barbara Boxer (D-Calif.) responded to the Republican boycott by saying McCarthy was "perhaps the most qualified nominee to ever head the EPA," calling the Republicans on the committee "out of the mainstream" and referring to their boycott as "obstructionist." EPW committee rules require at least two members of the minority party to be present to constitute a quorum, which is necessary for the committee to take action. However, Democratic lawmakers at the meeting urged Boxer to consider revising the rules to allow all 10 Democrats to approve her nomination to allow a vote by the full Senate.

On May 8, Republicans also were able to delay a scheduled vote on Perez, currently head of the Justice Dept.'s civil-rights division. Senate Republican Leader Mitch McConnell (R-Ky.) calls Perez a "crusading ideologue" who "circumvents or ignores a law with which he disagrees."

But on the Senate floor, Tom Harkin, chairman of the Senate labor committee, challenged McConnell's characterization. "I would respectively suggest that the minority leader needs to check his facts." He also said that, despite the controversy, "There is absolutely nothing that calls into question [Perez's] ability to fairly enforce the law as it is written, his professional integrity or moral character or his ability to lead the Dept. of Labor."

Votes in both committees have been rescheduled for May 16.