Senate Republicans blocked a confirmation vote on President Obama’s pick to lead the Environmental Protection Agency by boycotting a committee meeting Thursday. They are accusing Gina McCarthy of issuing “unresponsive answers” to more than 1,000 written questions about EPA policies and practices. McCarthy currently leads the EPA’s Office of Air and Radiation after being easily confirmed for that post by the Senate in 2009. The move came one day after Senate Republicans delayed a vote on Obama’s pick for labor secretary, Thomas Perez.