(AP) — A series of fiery train crashes spurred a push by government and industry to make safer tank cars used to ship crude oil and ethanol. But the effort is bogging down in squabbling and finger-pointing.

A spokesman for the American Petroleum Institute says the railroad industry won’t share data behind their recommendations to make the cars safer. He says the oil industry wants a “comprehensive examination” of proposed changes.

But the Transportation Department says it’s the oil industry that won’t share its data on the dangers of the oil being shipped. The department is drafting regulations aimed at making the cars less likely to spill their contents in the event of a crash.

National Transportation Safety Board Chairman Deborah Hersman says it’s time for a referee to step in.