"Needless to say, industrial employers across the country feel vindicated by this common sense ruling," he added.

In the case of Chevron v. Echazabal, the issue was whether a regulation issued by the Equal Employment Opportunity Commission, which allows a company to refuse to hire an individual for a job that would endanger his or her own health, is superceded by the ADA.

In a unanimous decision written by Justice David Souter, the court said that ADA does not nullify the EEOC rule.

The case involves one Mario Echazabal, who worked for an independent contractor at an oil refinery owned by Chevron. He twice applied for a job with Chevron, but was turned down following a physical examination, which revealed a liver abnormality, which would be aggravated by exposure to toxins at the Chevron refinery.

Moreover, as a result of the examination, Chevron asked the independent contractor to reassign Mr. Echazabal to a job where he would not be exposed to toxins.

Eventually, the contractor laid off Mr. Echazabal. He then filed suit against Chevron, charging that its refusal to hire him, or even allow him to continue working in the plant for the independent contractor due to his liver condition, violated the ADA.

Chevron responded that the EEOC regulation allowed its action, and the high court agreed. The court said the the EEOC rule is reasonable. Since Congress has not spoken exhaustively on this issue, the court said, the rule should stand.