WASHINGTON — The Republican chairman and ranking Democrat on the House Homeland Security Committee said they want the head of the Transportation Security Administration to explain how racial profiling became a common practice among TSA screeners at Newark Liberty International Airport. Rep. Peter King (R-N.Y.) and Rep. Bennie Thompson (D-Miss) are both seeking answers from TSA Administrator John Pistole, after a federal report found several behavior detection officers, or BDOs, had singled out Mexican and Dominican passengers for special scrutiny, bag searches, questioning and document reviews in 2008 and 2009.