Sixty-two cities in the United States have been deemed "high threat urban areas" by the Department of Homeland Security, meaning they’re susceptible to attack by terrorists targeting railroad tank cars loaded with chlorine gas or other deadly poisons. Under a 2007 law, freight rail companies were ordered to analyze their operations in these and other areas and select the "safest and most secure practicable" routes for hazardous cargo.

The analysis is complete, according to the Federal Railroad Administration. But some elected officials and emergency responders say they’re being kept in the dark. "Regulations issued last year give the ...