The massive, non-nuclear Divine Strake explosion planned for the Nevada Test Site will be postponed three weeks until June 23, according to papers filed Friday in U.S. District Court in Las Vegas.

An emergency motion filed by attorney Robert Hager on behalf of some members of the Winnemucca Indian Colony and some downwinders in Nye County and Utah demands that federal agencies submit information from "secret briefings" and data from recent radiological surveys of the experiment site, 85 miles northwest of Las Vegas.

The motion refers to a telephone conversation between Hager and Justice Department lawyer Sara Culley and other federal attorneys in Washington, D.C.

Hager said the lawyers responded to demands he made in a letter to Culley on Wednesday, saying the blast originally set for June 2 would be cancelled and "the new scheduled blast date is June 23."

In addition, U.S. attorneys promised to hand-deliver a revised environmental assessment for the Divine Strake test. That occurred Friday, Hager said by telephone from Reno.

Hager said the lawyers told him the National Nuclear Security Administration, which is hosting the test for the Defense Threat Reduction Agency, would issue a final decision Tuesday on whether to proceed with a formal, environmental impact statement or issue a finding of no significant impact.

Regardless of the outcome, Hager said, the NNSA is required to give the public 15 days to comment on its revised environmental assessment.

"They're making a mockery of federal environmental laws by telegraphing the expected explosion date before the agency makes a decision on whether an environmental impact statement is required," Hager said late Friday.

In his emergency motion, Hager wrote, "The fact that defendants propose to schedule the blast before the decision on whether an EIS is required reflects a lack of concern for the public health of downwinders, and of applicable legal requirements."

Downwinders and Western Shoshones from the Winnemucca Indian Colony filed a lawsuit April 20 to block the Divine Strake explosion, which they fear will create a dust-filled mushroom cloud that will spread hazardous pollutants and surface contamination from past nuclear bomb tests at the Nevada Test Site.

State environmental officials also have expressed concerns.

They have told NNSA officials they will not allow the detonation of 700 tons of ammonium nitrate and fuel oil to go off as planned until they have received all information requested and have conducted a thorough review to ensure all state and federal air quality laws will be met and that the cloud will be tracked and monitored by independent experts.

Late Friday, an NNSA spokesman and a spokeswoman for the Defense Threat Reduction Agency said there has been no announcement by either agency of a postponement of the test although their attempts to reach government lawyers late Friday were unsuccessful.

Kevin Rohrer, a spokesman for the NNSA's Nevada Site Office, said a revised environmental assessment with additional data on radiological sampling was posted Friday on the Department of Energy's Web site.

"The data show no contamination on the mountainside where the test will be conducted," he said, noting that the distance to the closest surface contamination had been clarified to where a muck pile sits from previous tunnel tests, 1.1 miles from the expected Divine Strake crater area.

Agency scientists have said the $23 million Divine Strake test is designed to assess how shock waves from existing and future weapons travel through limestone to destroy a tunnel where weapons of mass destruction are stored.

The effort, the culmination of a series of some 45 experiments in the tunnel area, parallels a program to explore more powerful conventional explosives.