The Senate Environment and Public Works Committee yesterday unanimously approved Lee M. Thomas as administrator of the Environmental Protection Agency after a brief hearing that turned up nothing but praise for his nomination.

"Experience shows that he is good at what he does," committee Chairman Robert T. Stafford (R-Vt.) said of Thomas, who in 1983 took over management of the agency's foundering Superfund program to clean up toxic-waste dumps.

Other senators were equally laudatory, prompting Stafford to comment, "This is one of the better bipartisan launchings we've had." Several environmental groups also testified in support of Thomas, praising his "competence and integrity."

But there were some pointed questions, most of them directed over Thomas' shoulder at the Office of Management and Budget.

Some members of Congress have privately expressed doubt that Thomas, a career government employe, has the political clout to win the inevitable showdowns with the OMB, which has sharply expanded its power over executive agencies in recent years.

Environmentalists who testified yesterday accused the OMB of blocking proposals to improve clean-water and toxic-waste laws, thwarting a modest acid-rain control program and delaying dozens of rules intended to curb hazardous pollutants.

"If Lee Thomas does not have the political stature now, it is his job -- indeed it is his legal obligation -- to develop it," Stafford said.

Stafford's committee submitted more than 30 pages of written questions to the EPA in advance of yesterday's hearing, most of them dealing with a recent executive order that would give the OMB sweeping new authority over federal agencies' regulatory agendas.

The panel got less than three pages of answers back, and Thomas acknowledged that the EPA's responses "have been coordinated with OMB."

But he dismissed suggestions that the order would have a major impact on the EPA's work. "Relatively few of the actions that we take fall into the category of significant under that document," he said.

Thomas, 40, a former South Carolina safety official, came to the EPA from the Federal Emergency Management Agency, where he won praise for his handling of a federal buyout of the dioxin-contaminated town of Times Beach, Mo.

In his statement yesterday, Thomas made it clear that he will maintain the course laid out by his predecessor, William D. Ruckelshaus.

"We are an industrialized society, and we will always be faced with environmental risks," he said. "It is simply one of the prices we pay for the overall quality of life we enjoy. Thus, we must learn to manage the risks we face."

Thomas also repeated Ruckelshaus' pledge to operate the EPA "in a fishbowl" and said he was committed to a strong enforcement effort. He added, however, that "enforcement need not dominate our implementation of environmental laws."

In response to a question on acid rain, Thomas told the panel that he cannot say when the administration's policy of more research might lead to a proposal for action. "The more I have learned of this issue, the more I am convinced that the study must go on," he said.

He also said that the administration was not ready to make a recommendation for renewing the Superfund toxic-waste cleanup law, which expires in September.

President Reagan's budget requests $900 million for Superfund in fiscal 1986, but the administration has yet to explain how it intends to raise the money, none of which would come from general revenues.