Oct. 31, 2009 (United Press International) -- A Canadian company that allegedly sold defective Zylon fabric -- a key ballistic material in bullet-proof vests -- is being sued by the U.S. Justice Department.

In a release issued Friday, Justice Department officials said they filed suit against Lincoln Fabrics Ltd. and its American subsidiary under the False Claims Act, alleging they were aware the woven Zylon used in vests sold to the U.S. government degraded quickly over time, especially in hot and humid conditions.

Tony West, assistant U.S. attorney general for the department's civil division, said Lincoln knew the degradation rendered the vests useless and that, despite this knowledge, it didn't inform the government or stop selling woven Zylon for ballistic applications.

"Companies that knowingly sell the government defective bullet-proof vests not only submit false claims, they put the lives of our law enforcement personnel at risk," said West. "The United States takes very seriously allegations that these two companies knowingly participated in the manufacture and sale of defective bullet-proof vests."

He said other lawsuits are being pursued against Toyobo Co., the manufacturer of the Zylon fiber; Honeywell International Inc. (NYSE:HON) , the manufacturer of a Zylon laminate product called Z Shield; and others in connection with the vests.