The concessions to the enviro's also mean the facility is more likely to experience a spill.
In BNSF's concessions, smaller storage tanks were installed meaning instead of the tanks being refilled once a day or every other day, they have to be recharged daily, sometimes more than once. All this switching of the tank farm and connecting and reconnecting of tank cars increases the likelihood of an accident and spill. Had it been built as planned, switching of the tank farm would happen much less often and fewer people would be handling the process, and it would be done at a much more relaxed pace, reducing the spill potential.
Also, the refueling of trains takes place at a hurry up pace due to the reduced size of the facility, also increasing the chance of a spill. Containment areas were also reduced with the size of the facility.