The Justice Department stepped between Congress and Environmental Protection Agency Administrator Anne Gorsuch yesterday, formally citing executive privilege in backing her refusal to produce thousands of documents that Congress wants to see.

Congressional staff members viewed the move as an escalation of Reagan administration efforts to withhold information that previous administrations supplied routinely to congressional committees.

"This has nothing to do with the president and there is no legal basis for executive privilege," said one staff official. "They're using this as a way to avoid scrutiny."

Rep. Elliott H. Levitas (D-Ga.), chairman of the House Public Works and Transportation investigations subcommittee, had subpoenaed Gorsuch to appear on Thursday with all documents concerning the 160 toxic waste sites targeted for cleanup by EPA's so-called "Superfund," while Rep. John D. Dingell (D-Mich.) subpoenaed her to produce documents on three of the sites for his Energy and Commerce oversight subcommittee.

The subcommittees argue that they need the data to see whether Superfund and the EPA are working as Congress intended. Dingell said he would not make public any of the documents without the consent of his full subcommittee. But Gorsuch refused, saying the papers involve ongoing legal matters and would reveal EPA's tactics for getting those responsible for the dumps to clean them up. She is still scheduled to appear Thursday, her office said.

In a letter to Dingell, Attorney General William French Smith cited precedents back to George Washington as holding that the president cannot allow Congress to decide on the secrecy of a document.

"At bottom, the president has a responsibility vested in him by the Constitution to protect the confidentiality of certain documents which he cannot delegate to the executive branch," the letter said.

Writing to Levitas, Smith said his request involves 787,000 documents. He said he hoped Levitas would drop the matter.

The subcommittees now have several options, according to Justice Department spokesman Thomas P. DeCair: they can drop the request, modify it, hold Gorsuch in contempt of Congress, or enact a law giving the federal courts jurisdiction to decide whether executive privilege applies in this case. DeCair said a court denied congressional efforts to obtain certain documents during the Watergate investigations of 1974.