New evacuations were ordered Friday near a train derailment in southern New Jersey involving tanker cars filled with toxic chemicals, emergency officials said. US Coast Guard Lt. Drew Madjeska said people living within 12 blocks of the bridge over Mantua Creek in Paulsboro might be out of their homes for several days, The Philadelphia Inquirer reported. About 500 people were affected. Several cars on the long freight train derailed at about 7:15 a.m. when a bridge over the creek collapsed. Four tanker cars carrying vinyl chloride went into the water, rupturing one of them. Assistant Paulsboro Fire Chief Gary Stevenson said about half of the vinyl chloride remains in the tanker and water could be leaking in. The slushy material turns into a gas if mixed with water. Stevenson said air tests showed \"spiking\" levels of vinyl chloride in late afternoon. Earlier in the day, environmental officials had suggested any air problems would be short-lived because the gas dissipates quickly. The bridge, near where Mantua Creek joins the Delaware a few miles downriver from Philadelphia and Camden, N.J., was repaired after a 2009 collapse. That collapse spilled rail cars loaded with coal into the creek.