WASHINGTON (AP) — The head of the National Transportation Safety Board is expressing alarm at a dramatic increase in hazardous liquids being hauled in freight trains.

NTSB Chairman Deborah Hersman says that while crude oil, ethanol and similar substances used to fill a single tank car of a train, there are now whole trains of 100 cars hauling "millions of gallons of this hazardous liquid." She says these trains "are running through a lot of people's back yards." According to Hersman, these rail shipments have increased 440 percent since 2005.

And she says communities aren't prepared to respond to potential accidents such as the oil train derailment that killed nearly 50 people and devastated an entire town in Canada last summer. Hersman says there are no provisions in place to deal with it, "either on the industry side or for the first responders."  So the NTSB is beginning a two-day forum today for experts from the petroleum industry, the railroad industry and first responders. They'll put their heads together with safety experts and try to find ways to prevent catastrophic accidents involving rail tank cars.