CHICAGO -- After 13 years at the Louisville, Mo., automobile battery manufacturing division of Johnson Controls Inc., Patricia Lynne Briner says her career is at a dead end.

"I can't go anywhere," said Briner, 39, whose job is to fill batteries with acid. "The good jobs are in departments where lead is used -- and women aren't allowed to work in them. The company says it's too dangerous. That includes women who aren't pregnant and who don't ever intend to become pregnant."

Citing fears about health risks, Johnson Controls, a $3.7 billion Milwaukee-based manufacturing company with 37,000 employees nationwide, won't let women work in areas of their 14 plants where lead is used unless the women have medical proof of their sterility.

The American Civil Liberties Union says that 15 major U.S. corporations have similar policies, among them American Cyanamid Co., Olin Corp., General Motors Corp., Gulf Oil Corp., B.F. Goodrich Co., Dow Chemical Co., Du Pont Co., Union Carbide Corp. and Monsanto Co.

Johnson's "fetal protection" policy has been challenged by eight female employees and the United Auto Workers. The U.S. Circuit Court of Appeals in Chicago ruled that the exclusion of women is not a violation of sex discrimination provisions of the U.S. Civil Rights Act, and is a "business necessity" in view of potential lawsuits. The U.S. Supreme Court will hear the case in September.

Hanging on the outcome is the availability to women of an estimated 20 million industrial jobs. The National Association of Manufacturers has filed a brief on the side of Johnson. A consortium of civil rights, women's and labor organizations has asked the court to reverse the decision.

"If lead exposure is that dangerous, it's dangerous for men, too," said Briner, who is not a litigant in the case. "I'm divorced and have two grown children. I don't intend to have more."

Briner earns $11.37 an hour. Jobs in leaded areas average $14 an hour, she said.

''But it's not the money, it's the discrimination that makes me mad,'' said Briner, a member of UAW. ''There are only a few jobs women can have -- while young men take the high-paying jobs and can advance.''

Sociologist Pauline B. Bart calls this exclusion of women ''the biggest protection racket in the world.''

But John Kennedy, general counsel for Johnson Controls, argues the company has the best interest of its female employees in mind. ''We had a voluntary policy concerning work in lead areas by women in place for several years, and during that time, six women got pregnant,'' he said. ''Even when women make a conscious choice not to get pregnant, they still do -- more than half of all pregnancies are unplanned.''

The company, he said, is in compliance with federal standards and ''could not solve the problem by taking additional steps to clean up the plant.'' He also said that according to company research, lead exposure ''has a minor impact on men, but an overwhelming evidence indicates risk to fetuses.''

A similar suit against the company in California was decided in favor of the women under the age of 70 who were excluded from battery-making jobs and resulted in a ruling of sex discrimination against the company.

In Detroit, a federal appeals court has ruled as discriminatory GM's policy of barring fertile women from jobs that expose them to lead.

''The so-called fetal-protection policy is harmful because it treats all women ages 18 to 70 as potentially bearing children, and at all times -- and as unable to make responsible decisions about their own fertility,'' said Vicki Schultz, assistant law professor at the University of Wisconsin in Madison.

''This case can be seen as another attempt to keep women from jobs that allow them to support themselves and their families independently.''

But there are safety and ethical issues involved, said Susan Benton-Powers, attorney with Sonnenschein, Nath & Rosenthal, a Chicago firm that represents management.

''The big concern for an employer is the safety of third parties, in this case the fetus,'' said Benton-Powers. ''Under {federal} regulations, companies must take affirmative steps to protect third parties from recognized workplace dangers.''

There are conflicting messages from workplace regulations and civil rights laws, she said. ''The Supreme Court will have to decide if this policy, which is discriminatory, is justified.''