Derailed freight train cars sit semi-submerged in the waters of Mantua Creek after a train crash in Paulsboro, New Jersey November 30, 2012. A rail bridge collapsed on Friday over a creek in southern New Jersey, causing a Conrail freight train to derail and spill hazardous chemicals into the air and water, authorities said. REUTERS/Andrew Burton
Derailed freight train cars sit semi-submerged in the waters of Mantua Creek after a train crash in Paulsboro, New Jersey November 30, 2012. A rail bridge collapsed on Friday over a creek in southern New Jersey, causing a Conrail freight train to derail and spill hazardous chemicals into the air and water, authorities said. REUTERS/Andrew Burton
Workers investigate a train derailment in Paulsboro, N.J. on Friday, Nov. 30, 2012 that is leaking hazardous material into a creek and causing a leak of hazardous gas that was blamed for sickening dozens of people, authorities said. ( AP Photo/Philadelphia Daily News, Alejandro A. Alvarez)
Derailed freight train cars sit semi-submerged in the waters of Mantua Creek after a train crash in Paulsboro, New Jersey November 30, 2012. A rail bridge collapsed on Friday over a creek in southern New Jersey, causing a Conrail freight train to derail and spill hazardous chemicals into the air and water, authorities said. REUTERS/Andrew Burton
Officials stand next to derailed freight train cars in Paulsboro, N.J., Friday, Nov. 30, 2012. People in three southern New Jersey towns were told Friday to stay inside after the freight train derailed and several tanker cars carrying hazardous materials toppled from a bridge and into a creek. At least one tanker car may contain vinyl chloride, Gloucester County Emergency Management director J. Thomas Butts told WPVI-TV. (AP Photo/Mel Evans)
Derailed freight train cars sit semi-submerged in the waters of Mantua Creek after a train crash in Paulsboro, New Jersey November 30, 2012. A rail bridge collapsed on Friday over a creek in southern New Jersey, causing a Conrail freight train to derail and spill hazardous chemicals into the air and water, authorities said. REUTERS/Andrew Burton
Derailed freight train cars lie scattered near the tracks in Paulsboro, N.J., Friday, Nov. 30, 2012 with a refinery in the background. The freight train derailed on a railroad bridge that has had problems before, toppling tanker cars partially into a creek and causing a leak of hazardous gas that was blamed for sickening dozens of people, authorities said. (AP Photo/Mel Evans)
Several cars lay in the water after a freight train derailed in Paulsboro, N.J., Friday, Nov. 30, 2012. People in three southern New Jersey towns were told Friday to stay inside after the freight train derailed and several tanker cars carrying hazardous materials toppled from a bridge and into a creek. (AP Photo/Cliff Owen)
Emergency personnel respond to an intersection close to where a freight train derailed in Paulsboro, N.J., Friday, Nov. 30, 2012. People in three southern New Jersey towns were told Friday to stay inside after the freight train derailed and several tanker cars carrying hazardous materials toppled from a bridge and into a creek. (AP Photo/Cliff Owen)
Several cars lay in the water after a freight train derailed in Paulsboro, N.J., Friday, Nov. 30, 2012. People in three southern New Jersey towns were told Friday to stay inside after the freight train derailed and several tanker cars carrying hazardous materials toppled from a bridge and into a creek. (AP Photo/Cliff Owen)
Several cars lay in the water after a freight train derailed in Paulsboro, N.J., Friday, Nov. 30, 2012. People in three southern New Jersey towns were told Friday to stay inside after the freight train derailed and several tanker cars carrying hazardous materials toppled from a bridge and into a creek. (AP Photo/Cliff Owen)
Derailed freight train cars, one marked "vinyl chloride", lay in water in Paulsboro, N.J., Friday, Nov. 30, 2012. People in three southern New Jersey towns were told Friday to stay inside after the freight train derailed and several tanker cars carrying hazardous materials toppled from a bridge and into a creek. (AP Photo/Cliff Owen)
Derailed freight train cars sit semi-submerged in the waters of Mantua Creek after a train crash in Paulsboro, New Jersey November 30, 2012. A rail bridge collapsed on Friday over a creek in southern New Jersey, causing a Conrail freight train to derail and spill hazardous chemicals into the air and water, authorities said. REUTERS/Andrew Burton
Several cars lay in the water after a freight train derailed in Paulsboro, N.J., Friday, Nov. 30, 2012. People in three southern New Jersey towns were told Friday to stay inside after the freight train derailed and several tanker cars carrying hazardous materials toppled from a bridge and into a creek. (AP Photo/Cliff Owen)
Derailed freight train cars sit semi-submerged in the waters of Mantua Creek after a train crash in Paulsboro, New Jersey November 30, 2012. A rail bridge collapsed on Friday over a creek in southern New Jersey, causing a Conrail freight train to derail and spill hazardous chemicals into the air and water, authorities said. REUTERS/Andrew Burton
Derailed freight train cars lay in water in Paulsboro, N.J., Friday, Nov. 30, 2012. People in three southern New Jersey towns were told Friday to stay inside after the freight train derailed and several tanker cars carrying hazardous materials toppled from a bridge and into a creek. (AP Photo/Cliff Owen)
Derailed freight train tank cars are seen in Paulsboro, N.J., Friday, Nov. 30, 2012. People in three southern New Jersey towns were told Friday to stay inside after a freight train derailed and several tanker cars carrying hazardous materials toppled from a bridge and into a creek. At least one tanker car may contain vinyl chloride, Gloucester County Emergency Management director J. Thomas Butts told WPVI-TV. (AP Photo/Mel Evans)