A recipe for making methamphetamine and some of the ingredients used in the drug were found by authorities after an explosion Saturday at a federal laboratory in Gaithersburg as police investigate whether an employee made the illicit drug on the site.

An explosion was reported about 7:30 p.m. Saturday on the campus of the National Institute of Standards and Technology, an agency within the U.S. Department of Commerce.

NBC Washington reports responders found a blast shield inside a NIST building had flown about 25 feet. Montgomery County Police told the TV station the blast may have been caused by a chemical reaction during the manufacture of drugs.