New Jersey firefighters have become increasingly worried that a train carrying Bakken fuel will cause a deadly explosion in the state.
Bakken fuel is a highly flammable crude oil.
Each day, at least one train carrying the substance makes its way to the refineries located in New Jersey from the Midwest, where the U.S. has seen resurgence in domestic oil production from fracking.
Since the beginning of 2015, there have been five train explosions and leaks in North America involving Bakken oil.
Some officials believe the explosions aren't always accidental.
"I personally believe these are terrorists derailing these trains," said Newark Deputy Fire Chief Anthony Castbllucio. "It seems the Bakken trains derail. You don't see trains with coal or cars derailing."
Newark Fire officials say containing a Bakken Fuel explosion is difficult since a large number of trains travel together, forming a mile-long line.
The explosion often takes place in the middle of a train, where the rail car is not fortified.
To prepare for the unexpected, the Newark and Elizabeth Fire Departments held a drill to simulate an explosion, using specialized fire foam on the scene.
Meanwhile, the U.S. Department of Transportation unveiled new rules for transporting crude oil by trains in May.
The standards regulate the trains' brake equipment and speed.