WASHINGTON - Nevada Gov. Kenny Guinn and state officials are demanding assurances that a massive blast planned at the Nevada Test Site won't violate environmental laws, saying the test can't proceed until they give the go-ahead.

The Pentagon says Nevada will get the information it wants, and the detonation of 700 tons of explosives will go ahead June 2 as planned.

Labeled Divine Strake, the test was billed in Defense Department documents as a way to help war planners choose the smallest nuclear weapon needed to destroy buried targets, such as bunkers or tunnels. The department now says the nuclear reference was a mistake and the test is for conventional purposes only.

Nevada Division of Environmental Protection Administrator Leo Drozdoff said in a letter to the federal Test Site operator that it must provide Nevada with emissions models for the blast and assurances the test will not violate state or federal air standards.

"Once that information is received, [the state agency] will make a determination as to whether the test complies with" Nevada law, Drozdoff wrote to the National Nuclear Security Administration. "NNSA is prohibited from allowing this test to proceed until authorization from [the state agency] has been received."

Nevada officials review specific tests at the site to ensure they comply with general permits.

"The Governor's Office expects the NNSA to fully comply with all applicable state environmental rules and regulations before any testing is done," Guinn's deputy chief of staff, Steve Robinson, said in a statement.

Irene Smith, spokeswoman for the Pentagon's Defense Threat Reduction Agency, said that, based on modeling done for a potential 940-ton blast, emissions from the test are expected to be within the limits of the test site's air permit, and the test would only be allowed if certain weather conditions are met.

However, she said, NNSA plans to do additional computer modeling to meet Nevada's concerns and will provide that information to the state within two weeks.

"We're still planning on holding the test," Smith said. "It has not been postponed or cancelled."

The Divine Strake test consists of the detonation of 700 tons of explosives above a tunnel. Computers will measure the damage to the tunnel and ground shaking in the area.

There is concern that the test could be used to develop a new generation of low-yield tactical nuclear weapons, based on the Pentagon budget document and the size of the explosion - five times larger than the largest existing conventional weapon, but many times smaller than the country's smallest nuclear weapon.

In 2003, the Bush administration convinced Congress to partially repeal its ban on development of tactical nuclear weapons.

Rep. Jim Matheson, D-Utah, raised concerns about the potential for new nuclear development in a letter to the Defense Threat Reduction Agency.

He also asked for additional details on the test and assurances that Utahns across the border will not be endangered.

Nevada Sen. Harry Reid and Rep. Shelly Berkley, had expressed concern about the test, but after a briefing with Pentagon officials both said they were reassured the test could be conducted safely.