Seven of the train's cars derailed Friday when a bridge over Mantua Creek collapsed and the chemical leaked from a punctured tank car, the South Jersey Times, Woodbury, reported.
During the cleanup effort early Monday, monitors picked up the elevated vinyl chloride levels, but they were "100 times less" than amounts that could cause health risks, Coast Guard Capt. Kathy Moore said.
Nonetheless, police advised nearby residents to stay indoors and area schools were closed.
2014: The Year in Music [PHOTOS]