They are just pieces of cardboard, and they cover less than a square foot on the side of railroad tank car. But behind them lies a post-9/11 competition between public safety and national security.
For decades, emergency-response teams approaching train wrecks have peered at the signs through binoculars to see what dangerous chemicals might be leaking. But federal officials will soon decide on a proposal to remove the placards from all tank cars. Their fear is that terrorists could use them to lock in on targets for highly toxic attacks.
The idea has sparked an outcry from firefighters and rail workers, who say removing the signs could endanger their lives. They say federal officials seem more focused on guarding against a terrorist attack than on the daily threat of accidents.
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People who live near chemical and nuclear plants, dams and oil and gas pipelines complain that it has become harder to find out about disaster plans and environmental hazards, and some have sued for more information. Engineering reports have been stripped from government Web sites, and several agencies are creating new controls on sensitive information that go far beyond the wide-ranging classification system built in the cold war.
http://nytimes.com/2005/03/05/national/05secret.html?hp&ex=1109998800&en=ed065efae7d98458&ei=5094&partner=homepage