The nation's largest manufacturer of bulletproof vests for police was accused in a lawsuit brought by Pennsylvania's attorney general Tuesday of failing to disclose for years that the material in some models deteriorates with exposure to fluorescent light, heat and humidity.

Attorney General Jerry Pappert (search) blamed the vests for the death of a police officer in California and the wounding of an officer in suburban Pittsburgh.

The state is demanding Second Chance Body Armor Inc. (search) of Central Lake, Mich., pay hundreds of thousands of dollars in civil penalties and give refunds to Pennsylvania law enforcement agencies that bought the lightweight vests.

Second Chance president and chief executive Paul Banducci said the company had not seen the lawsuit, but he added that Second Chance has properly handled the issues, voluntarily replacing or upgrading thousands of vests.

Pennsylvania is the sixth state to file such a lawsuit against Second Chance. Second Chance sold more than 7,200 of the lightweight vests worth nearly $5 million to 200 law enforcement agencies around the state, including the Pennsylvania State Police, Pappert said.

Second Chance discontinued production of the lightweight vests last September, Pappert said.

The vests used Zylon fibers — a material produced by Toyobo Co. of Japan — that made the body armor lighter and more comfortable.

But in December 1998, Toyobo informed Second Chance that the material significantly deteriorated with exposure to fluorescent light, Pappert said. And in August 2001, he said, Toyobo officials told Second Chance that heat and humidity tests resulted in more problems.

"It's our position that Second Chance made a conscious decision to hold off warning our law enforcement officials that degradation problems with Zylon in bulletproof vests could seriously compromise their effectiveness," Pappert said.