Updated

The Pentagon spent $10.2 billion over three decades burning chemical weapons stored in four states. Now, with those chemicals up in smoke and communities freed of a threat, the Army's in the middle of another, $1.3 billion project: Demolishing the incinerators that destroyed the toxic materials.

In Alabama, Oregon, Utah and Arkansas, crews are tearing apart multibillion-dollar incinerators or working to draw the curtain on a drama that began in the Cold War, when the United States and the former Soviet Union stockpiled millions of pounds of chemical weapons.

Construction work continues at two other sites where technology other than incineration will be used to neutralize agents chemically.

Critics called the incinerators dangerous. Officials say no residents living nearby were exposed to chemical agents or injured during years of work.