The U.S. Coast Guard says a 12-block evacuation near the site of a southern New Jersey train derailment remains in effect for precautionary reasons. This extended evacuation follows eariler assurances from state health officials who on Friday said there is no risk from from the thousands of gallons of vinyl chloride that released into air

NBC10 reports that eariler this morning media were instructed to leave the area near a train derailment in Paulsboro, New Jersey Monday morning after crews determined there was a rise in chemical levels.

Officials say about 100 Paulsboro residents will be kept out of their homes for several more days as crews work to clear a hazardous gas that spewed from a ruptured freight train car. On Sunday, heavy fog delayed clean-up efforts around the accident site.

Public schools are closed on Monday and municipal courts will be closed. The derailment Friday sent dozens of people to a hospital, but no serious injuries have been reported.

The NTSB investigation

The head of the National Transportation Safety Board says investigators looking into a New Jersey train derailment will focus on a signal and a bridge's locking mechanisms.

Investigators say other railroad crews have reported possible problems with a signal where a train derailed on aNew Jersey rail bridge, spewing a hazardous chemical into the air. National Transportation Safety Board Chairwoman Deborah Hersman says investigators will focus on the signal and bridge's locking mechanisms.