Washington ? The Supreme Court on Wednesday wrestled with the workplace rights of recovering drug addicts and alcoholics in a case with implications for thousands of employers and more than 5 million workers with substance abuse problems.

The justices are considering whether an Arizona missile plant worker who lost his job after testing positive for drugs deserved to be rehired after getting sober.

The case of Joel Hernandez requires the court to clarify protections for workers under the landmark Americans With Disabilities Act.

The law specifically protects people who are clean after being treated for their addiction, but allows companies to discipline those who use substances on the job.

At issue is Hughes Missile Systems’ treatment of the 25-year employee, who was tested for drugs when he came to work one day in 1991 and reeked of alcohol. Hernandez quit when the test showed he had used cocaine. More than two years later, after completing drug and alcohol treatment, he was rebuffed when he tried to get rehired.

The company had an unwritten policy against rehiring workers who broke rules.

The Bush administration argued that Hughes, now owned by Raytheon Co., and other companies should be allowed to permanently bar workers for misconduct such as showing up on the job while high on drugs or alcohol.

Hernandez’s lawyer, Stephen Montoya of Phoenix, said his client has embraced religion and overcome drugs and alcohol. His recovery should trump Hughes’ policy of never rehiring a rule-breaker, Montoya told the justices.

Hernandez, who said he earns much less now as a maintenance supervisor at a shopping center, attended the arguments.

“After considerable rehab, I turned my life around and went back to apply for a job that I qualified for,” he said afterward. “I was trying to re-establish myself.”

The Supreme Court has never sided with an employee or former employee in cases testing the reach of the ADA in the workplace. At least two justices, Sandra Day O’Connor and Ruth Bader Ginsburg, questioned whether the Hernandez case was in the right posture for a Supreme Court ruling.

The 9th U.S. Circuit Court of Appeals ruled that a jury should decide if Hernandez was a discrimination victim under the 1990 disabilities law.

Groups such as the Betty Ford Center and National Council on Alcoholism and Drug Dependence filed briefs supporting Hernandez, arguing that most families have experience with addiction and that millions of people have overcome it.