The Homeland Security Department on Thursday recommended keeping warning signs on rail cars that carry hazardous materials (search) despite concerns that such placards could turn those trains into terror targets.

Firefighters and other emergency first responders vigorously oppose eliminating placards that alert them to take precautions during train derailments and other hazmat situations. The Homeland Security and Transportation departments began weighing the change after the Sept. 11, 2001, terror attacks (search).

Announcing the decision at a National Fire and Emergency Services dinner, Homeland Security Secretary Michael Chertoff (search) acknowledged the risk of "whether by identifying hazardous material, we are giving people a target, or a bull's-eye."

But, Chertoff said, "when you go out and you confront an emergency and a hazard, you have to know what it is you are facing. You have to know if you've got a chemical problem. You've got to know if there's some kind of explosive problem. And you need to have the kind of warning that those placards give you."

Chertoff's announcement effectively ends the debate over scrapping diamond-shaped rail placards that are often identified by a skull and bones symbol for poisons, or a number corresponding to a specific toxic chemical.

The Transportation Department has jurisdiction over hazmat materials on railways. Spokesman Brian Turmail said the joint decision with Homeland Security to keep the placards marks "the right combination that addresses security and safety in the transport of hazardous materials."

"It's the right move to protect first responders and to ensure the safe movement of the materials that fuel the American economy," Turmail said.

Lawmakers have pointed to recent train accidents — including a chlorine gas leak in South Carolina and a Utah spill — in arguing for the placards. Nine people were killed and hundreds injured as a result of the South Carolina leak in January, while 6,000 people were evacuated in Utah after a brew of acids leaked from the corroded sides of a railroad tank car.

Sen. Charles Schumer, D-N.Y., who wrote Chertoff last month to protest the proposal, said dropping the placards would put entire communities at risk.

"It made no sense to play blind man's bluff with a tank car that might be filled with hazardous materials," Schumer said Thursday.