Those affected were notified by reverse 911.
The order was issued due to another spike in air samples of vinyl chloride from the train wreck.
A shelter in place order means for residents to stay inside their homes.
Earlier in the day, the National Transportation Safety Board says the New Jersey bridge where a train derailed last week had several recent signal and alignment problems.
NTSB chairman Deborah Hersman says inspectors checked out the Paulsboro bridge on Thursday after signal problems were reported.
After that, several trains crossed without problems.
But after the last one that night cleared the bridge, its crew got a radio message that the bridge failed to operate.
Hersman says that may have been an indication that the bridge did not properly swing open to traffic on Mantua Creek below.
She says when the train that derailed pulled up just before 7 a.m. Friday, the bridge signal light was red. That could be an indication that it was not locked into place.
Meanwhile, some politicians have said the accident points to a bigger problem of heavy trains passing over aging infrastructure.
The low bridge that partially collapsed last week was originally built in 1873.
Several schools, preschools and daycare centers will be closed for the rest of this week as the cleanup of the derailed train cars continues:
Tracy Day Care
Billingsport Early Childhood Center
Paulsboro High School
Parents should contact the schools directly for more information about the closings.