Police Lt. David Spicer took four .45-caliber slugs to the chest and arms at point-blank range and lived to tell about it. Like thousands of other police officers and soldiers shot in the line of duty, he owes his life to a woman in Delaware by the name of Stephanie Kwolek.

Kwolek, who died Wednesday at 90, was a DuPont chemist who in 1965 invented Kevlar, the lightweight, stronger-than-steel fiber used in bulletproof vests and other body armor around the world.

A pioneer as a woman in a mostly male field, Kwolek made the breakthrough while working on specialty fibers at a DuPont laboratory in Wilmington, Delaware. At the time, DuPont was looking for strong, lightweight fibers that could replace steel in automobile tires and improve fuel economy.

"I knew that I had made a discovery," Kwolek said in an interview several years ago that was included in the Chemical Heritage Foundation's "Women in Chemistry" series. "I didn't shout 'Eureka,' but I was very excited, as was the whole laboratory excited, and management was excited because we were looking for something new, something different, and this was it."

Officer Spicer was wearing a Kevlar vest when he was shot by a drug suspect in 2001. Two rounds shattered his left arm, ripping open an artery. A third was deflected by his badge. The last one hit his nametag, bending it into a horseshoe shape, before burrowing into his vest, leaving a 10-inch tear.

"If that round would have entered my body, I wouldn't be talking to you right now," the Dover police officer said.

While recovering from his wounds, Spicer spoke briefly by telephone with Kwolek and thanked her.

"She was a tremendous woman," he said.

In a statement, DuPont CEO and Chairwoman Ellen Kullman described Kwolek, who retired in 1986, as "a creative and determined chemist and a true pioneer for women in science."

Kwolek is the only female employee of DuPont to be awarded the company's Lavoisier Medal for outstanding technical achievement. She was recognized as a "persistent experimentalist and role model."

"She leaves a wonderful legacy of thousands of lives saved and countless injuries prevented by products made possible by her discovery," Kullman said.