Robert E. Rader Jr., a controversial nominee to the Occupational Safety and Health Review Commission, was ordered by a federal judge to pay a $3,000 penalty last October for apparently misrepresenting facts and failing to comply with court orders in a race discrimination lawsuit in which he represented a Texas manufacturer.

Rader was "disingenuous" in statements to the court and apparently "misrepresented the facts" regarding his client's failure to produce documents requested by plaintiffs over a three-year period, according to a ruling by U.S. District Court Chief Judge William Wayne Justice in Tyler, Tex.

Rader, whose nomination by President Reagan has sparked sharp opposition from Senate Democrats, said yesterday that he has hired a lawyer to appeal the $3,000 sanction, and said he believed Justice's action "is not supported by the transcript of that hearing."

Rader, whose client, Trinity Industries Inc., was found to have "intentionally discriminated" against black employes, had refused to deliver some information sought by the plaintiffs because he believed much of the data was "irrelevant" to the case and would be very costly for the company to produce, according to Rader's lawyer, Robert Martin of Dallas.

Sen. Howard M. Metzenbaum (D-Ohio), chief critic of the Rader nomination, yesterday asked Sen. Orrin G. Hatch (R-Utah), chairman of the Labor and Human Resources Committee, to reconvene the nomination hearing. "Mr. Rader's personal and professional behavior in this matter raises serious additional questions about his fitness to serve" on the three-member panel that hears appeals of Occupational Safety and Health Administration (OSHA) citations, Metzenbaum said in a letter to Hatch. A Hatch spokesman said it is "very doubtful" that Hatch would reconvene the hearing.

Rader's nomination sparked strong opposition at a hearing March 12 because of Rader's legal advice to corporate clients that they resist and delay certain workplace inspections by OSHA.

A vote on the nomination is scheduled for May 14. Republicans control the committee by a 9-to-7 majority; staff members of both parties have said Rader's nomination could be killed on an 8-to-8 tie if the seven Democrats persuade Sen. Lowell P. Weicker Jr. (R-Conn.) to oppose it. Weicker has not indicated his position.

In the Texas case, Trinity Industries had been ordered six times to produce data needed by black employes to pursue their case, according to Judge Justice, who described the company's courtroom conduct as "intractable," "recalcitrant," "obstinately disobedient," "indifferent and disrespectful to established rules of procedure," and "a perversion" of proper advocacy.

The judge held a contempt hearing in 1984 on the company's failure to comply with his discovery orders, and Rader claimed at the hearing that he had brought boxes of documents to satisfy the order. The judge did not issue a contempt citation, but later learned that the boxes did not contain the documents in question.

"It appears that at that very hearing, the attorney misrepresented the facts in open court," Justice said, and ordered Rader to personally pay a $3,000 sanction to the plaintiff's lawyer. Such sanctions against lawyers are uncommon in federal courts, but are a lesser penalty than contempt citations.