The General Accounting Office will suggest today that a single federal agency be put in charge of the drug-testing program covering the government's 2.8 million civilian workers.

Officials of the congressional watchdog agency and the Office of Personnel Management are due to testify before the Senate Treasury, Postal Service, General Government appropriations subcommittee.

Chairman Dennis DeConcini (D-N.M.) and Sen. Barbara A. Mikulski (D-Md.) asked the GAO to examine agency programs to see if centralized management would improve them. Mikulski, who represents more than 100,000 federal workers, said she is concerned that programs are uncoordinated, and that many fail to protect the employees' rights.

The GAO's study concludes that there is no uniform drug-testing policy and no governmentwide oversight, and that rules vary from agency to agency and even within some departments.

Among its findings:

Penalties for employees found to be drug abusers vary greatly. Some agencies transfer employees; others fire them after a second (or first) offense.

Some agencies, such as Interior, the Defense Contract Audit Agency, General Services Administration, Agriculture, and Health and Human Services, pay as little as $8.90 to private laboratories for urinalysis tests while the Immigration and Naturalization Service paid $87, according to GAO auditors. Tests administered to FBI and Drug Enforcement Administration personnel cost about $18 each. In some cases the fees covered both the screen (initial) and a confirmation test. In others, the second test doubled or tripled the price.

Four years after President Reagan issued the executive order on drug-testing, some agencies still haven't tested employees. Some, such as Housing and Urban Development, test only non-union employees, while tests on union workers await the result of contract negotiations.

Agency policies on random testing (as opposed to testing all employees) vary greatly. For example, all Navy civilian workers with top-secret clearances are subject to random drug-testing. The Army, however, imposes random tests on certain people in selected positions with top-secret clearances. About 25 percent of all Navy employees are subject to the random tests, as opposed to only 2.4 percent of Army civilians, the GAO will report.

Alternative Fuel

The General Services Administration this year will test 60 cars -- 23 of them in the Washington area -- that run on either methanol or gasoline. The alternate-fuel Chevrolets and Fords will be driven by workers in the GSA; the Departments of Defense, Energy and Transportation; the Federal Energy Regulatory Commission; and the Environmental Protection Agency. It is part of a federal program to reduce dependence on foreign oil. The Postal Service has been testing cars that run on domestic natural gas for several years.

The GSA does most of the buying for the giant 300,000-vehicle federal fleet. Administrator Richard Austin said that the GSA's use of auto air bags as far back as 1981 helped break the ice for that safety breakthrough.