A former federal police officer was conducting an unauthorized training exercise when he tried to manufacture methamphetamine in a federal laboratory, leading to an explosion that injured the ex-officer, his lawyer said Tuesday.

Christopher Bartley, 41, plans to plead guilty to a single count of attempting to manufacture methamphetamine, said his attorney, Steven VanGrack. A court appearance is scheduled for Friday in federal court in Greenbelt, Maryland.

Bartley maintains that he was not manufacturing methamphetamine for his personal use but was instead trying to learn more about how the drug is made in order to train the officers he supervised, VanGrack said.

"He was conducting an unauthorized training experiment which failed, and he promptly admitted his responsibility for the incident and resigned," VanGrack said.

The explosion occurred July 18 on the campus of the National Institute of Standards and Technology in Gaithersburg, Maryland, about 15 miles north of the nation's capital.

Bartley was a lieutenant and supervisor with the institute's police force, said institute spokeswoman Gail Porter. He resigned his position a day after the explosion. He was treated at a hospital for injuries he suffered in the blast. No one else was hurt.

Authorities who responded to the explosion found pseudoephedrine, Epsom salt and other materials associated with the manufacture of meth.

Bartley is an Army veteran with no criminal record and no history of drug use, his attorney said.

"He does have a great track record and he represents that he's never used" illegal drugs, VanGrack said.

Bartley was charged Monday in a criminal information, a charging document that can only be filed with a defendant's consent and usually precedes a guilty plea.

He faces a maximum penalty of 20 years in prison but is likely to receive far less time under federal guidelines.

The building where the explosion occurred remains closed, but it will be available for experiments as needed, Burton said.

The institute, founded in 1901, is one of the nation's major physical science laboratories. It employs about 3,000 scientists, engineers, technicians, and support and administrative personnel.

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This story has been corrected to note that Bartley was charged Monday, not Tuesday.

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