Rep. John D. Dingell (D-Mich.), chairman of the House Energy and Commerce Committee, warned President Reagan in a letter yesterday that he has uncovered "evidence of wrongdoing, unethical behavior and potential criminal conduct" at the Environmental Protection Agency, and urged that the matter be considered for criminal prosecution.

EPA Administrator Anne M. Burford, appearing before a House Appropriations subcommittee with jurisdiction over the EPA, defended her leadership at the agency, but said she would support an independent investigation of the $1.6 billion Superfund program to clean up the nation's most dangerous chemical waste dumps.

"In light of the many, many allegations that have been made, it would behoove us all to appoint an independent commission to review all practices under Superfund and make recommendations to you and me," she said.

The EPA is facing six different congressional probes into charges of conflict of interest, political favoritism and mismanagement at the agency. The White House has fired or has ordered the resignations of several high-level EPA officials in recent weeks in an effort to strengthen the agency's leadership.

Dingell, who released his letter to the president in a news conference in the hallway outside the subcommittee offices, said he has learned that former EPA assistant administrator Rita M. Lavelle, fired by the White House Feb. 7, may have committed perjury last week in testimony before House and Senate committees.

During those hearings, Lavelle, who was in charge of the agency's Superfund operations, testified under oath that she was not aware until last June 17 that her former employer was a major dumper at the Stringfellow Acid Pits site in southern California. Lavelle has said that she formally withdrew from all decisions involving Stringfellow on June 18.

One EPA official told The Washington Post over the weekend that he had participated in a May 28 meeting at which Lavelle was warned specifically that her former employer, Aerojet-General Corp., had disposed of wastes at the Stringfellow site.

Referring to the May 28 meeting, Dingell said yesterday, "The committee has received sworn testimony of three EPA employes and the corroboration of a fourth that Ms. Lavelle was specifically advised on May 28" about the involvement of her former employer.

In his letter to the president, Dingell specifically said the subcommittee, which has been meeting in secret with present and former EPA employes, has received sworn testimony indicating that Lavelle's activities may have involved "unethical conduct and a conflict of interest" and that she may have violated federal laws against "perjury" and "fraud and false statements."

In fact, Lavelle's job at Aerojet led to her hiring at the EPA. In an interview last summer with the Environment Health Letter, Lavelle said she learned of the EPA opening while she was in Washington lobbying to have an Aerojet facility removed from the EPA's priority list of the nation's 115 most hazardous waste sites.

Lavelle, who was confronted by reporters as she left a closed-door meeting with Rep. Elliott H. Levitas (D-Ga.), chairman of a Public Works subcommittee investigating the EPA, appeared irritated by reports of Dingell's letter to Reagan.

"I would think that the chairman would conduct himself in accordance with House rules," she said, stating that nothing should have been forwarded until the investigation was complete.

Dingell, who has been trying for five months to persuade the EPA to turn over documents dealing with certain Superfund enforcement matters, said in the letter that he now believes those withheld documents "contain references to political manipulation."

Dingell said his investigation has led him to believe that some Superfund cleanup proposals were placed on an "election track."

Sources have said for several weeks that grants were speeded up or slowed with an eye toward helping the election prospects of administration friends.

Referring to a statement by Reagan in a recent news conference that he would never withhold documents to cover up wrongdoing, Dingell said:

"Mr. President, the time has arrived for you to meet your assurances. There exists more than a suspicion that documents are being withheld to cover wrongdoing."

In Santa Barbara, deputy White House press secretary Larry Speakes said the president has not received Dingell's letter, but he added:

"The president indicated he will not use executive privilege to cover up wrongdoing. He has instructed the Justice Department to look into wrongdoing.

"The administrator of the EPA referred certain allegations of wrongdoing to the Justice Department. We are willing to make documents available to Justice."

But congressional investigators have said often that they do not believe the Justice Department can be counted on to conduct an adequate investigation of matters at the EPA.

Rep. William H. Boner (D-Tenn.), a member of the EPA Appropriations subcommittee, said yesterday, "Asking Justice to investigate EPA is tantamount to asking the wolf to go count the chickens."

Burford said the agency has been hurt by the allegations of wrongdoing, but she defended her own record.

"I have a solid record of achievement at EPA," she said. "We have been given a difficult job, and I think we have done it pretty well . . . . We have been able to do it with fewer employes and . . . to reduce our budget."

She said the "circus atmosphere" is keeping the EPA from doing its job. "We can't operate in this atmosphere," she said. "I think the only way to remedy the situation is to get EPA out from under the position that we have something to hide . . . . We can't operate in this atmosphere."

Burford said she had referred the only instances of possible wrongdoing she knew about--ones concerning Lavelle--to the Justice Department.

Dingell, meanwhile, said that his subcommittee is broadening its probe into the EPA to include other programs within the agency besides Superfund.

He said the subcommittee has subpoenaed about a dozen additional current and former EPA employes to testify, in addition to the more than three dozen already under subpoena.

The subcommittee now has subpoenaed documents for five hazardous waste sites--two in Missouri and one each in California, Oklahoma and Michigan.

Dingell said the subcommittee has decided also to look into the EPA's handling of the Reilly Tar and Chemical Co. hazardous waste dump in St. Louis Park, Minn.

He said the subcommittee has requested documents about the site, but has not yet issued subpoenas.

The subpoenas already issued require Burford to appear March 10 with the documents.

After a similar subpoena last fall from another House subcommittee, Burford, under orders from Reagan, invoked executive privilege to withhold some of the documents, provoking the historic vote by the House last December to hold her in contempt of Congress.

The White House has reached a compromise with another House subcommittee over access to the disputed documents.

But that compromise is not binding on Dingell, and he said yesterday that he wants "immediate and total release" of the documents sought by his panel.