Christina Dodd rests her head on the shoulder of her dad, US Sen. Christopher Dodd (D) of Connecticut, after he announced Jan. 6, that he will retire after his current term. Dodd, who served five terms, is chairman of the Senate Banking Committee and made an unsuccessful bid for the presidency in 2008. Charles Krupa/AP
Sen. Ted Kaufman (D) of Delaware, is serving out the term of now-Vice President Joe Biden. He made clear all along that he would not seek election to the seat in his own right. Scott J. Ferrell/Congressional Quarterly
Sen. Roland Burris (D) of Illinois announced in July that he would not run for election in 2010. He was appointed to fill the seat formerly held by now-President Barack Obama. The terms of his appointment subsequently became a controversy. Charles Dharapak/AP
Sen. Evan Bayh (D) of Indiana, said Feb. 15 that he will not seek reelection to a third term. He cited Washington grid lock and partisan rancor. He's shown here at the 2008 Democratic National Convention in Denver, Colo. Mike Segar/Reuters/File
Sen. Byron Dorgan (D) of North Dakota said Jan. 6 that he decided against running for a fourth term because he wanted to pursue other opportunities, not because the prospect of a formidable challenger chased him from the race. Mike McCleary/The Bismarck Tribune/AP
Sen. George LeMieux (R) of Florida will retire after this year. Here, he takes part in a Feb. 4 news conference 'to introduce legislation to enact a one-year earmark moratorium and a Balanced Constitutional Amendment.' Newscom
Sen. Sam Brownback (R) of Kansas is giving up his senate seat to run for the gubernatorial seat in the Sunflower State. Manuel Balce Ceneta/AP
Sen. Jim Bunning (R) of Kentucky is not running for a third term. The Associated Press said he 'had been widely considered the most vulnerable Republican incumbent' heading into the 2010 elections, and the senate GOP leadership encouraged him not to seek reelection in order to find a candidate deemed more competitive. Saul Loeb/AFP/Newscom
Sen. Kit Bond (R) of Missouri is not seeking reelection to a fifth term. Missouri has been a swing state in recent elections. Newscom
In this Feb. 2 photo, the Senate Budget Committee's ranking Republican, Sen. Judd Gregg (R) of New Hampshire, meets with reporters on Capitol Hill in Washington. Senator Gregg said in Feb. 2009 that he would not seek reelection at the end of his current term, his third. Cliff Owen/AP
Sen. George Voinovich (R) of Ohio said in Jan. 2009 that he would not seek election to a third term. He won his last race, in 2004, with 64 percent of the vote. Newscom
Sen. Kay Bailey Hutchison (R), of Texas, decided to retire from the senate to run for governor. However, she lost the GOP preliminary in Texas to incumbent Gov. Rick Perry. Stephen Spillman/The Contra Costa Times/AP
Stolen radioactive cobalt-60 was found in central Mexico. The atomic energy agency said it is radioactive enough that 'it would probably be fatal to be close to this amount of unshielded radioactive material for a period in the range of a few minutes to an hour.'
Olga R. Rodriguez, Associated Press /
December 5, 2013
Officials were engaged Thursday in the delicate task of recovering a stolen shipment of highly radioactive cobalt-60 abandoned in a rural field in central Mexico state.