The specter of a mushroom cloud rising over the Nevada desert, sending radioactive dust and, along with it, disease and death eastward over Utah - that would be merely a scene from history, from the Cold War era 60 years ago when the federal government promised that nuclear tests were safe.
   At least that's what most Utah residents believed until a few months ago, when the National Nuclear Security Administration announced its Divine Strake test explosion, originally set for Friday, then postponed to June 23. Now, thanks to lawsuits by Utah Downwinders and pressure from Nevada officials and both states' congressional delegations, this misbegotten idea has been put on hold while the NNSA, finally, begins the due diligence on this potential threat to public health that it should have done in the first place.
   But, pending the outcome of more thorough assessments, the only way to ensure the safety of Utahns and others in the path of winds from the Nevada Test Site less than 100 miles from Las Vegas is to cancel the test altogether. Government assurances about the test's safety sound all too familiar to Utahns who lived through nuclear tests of the '50s and '60s and lost loved ones or their own health to their deadly effects.
   Although the 700-ton explosion would be non-nuclear, using the same type of chemical explosives - multiplied by 280 - that Timothy McVeigh detonated to destroy the Oklahoma City federal building, the test site is contaminated with radioactive dust from the open-air nuclear testing of decades ago.
   It's ridiculous for the NNSA to declare, as it has for months, that dust and debris kicked up into a 10,000-foot cloud raised by a blast nearly 50 times larger than the biggest known conventional weapon in the U.S. arsenal would somehow stay within the boundaries of the test site.
   Utah residents might have believed such a far-fetched claim in 1950, but now know better.
   Bush administration efforts to repeal a ban on development of low-yield nuclear weapons make it hard to believe its promises that Divine Strake is not a prelude to a new round of nuclear tests, but just a way to figure out how best to go after enemy underground bunkers.
   Divine Strake is of no certain value and probably dangerous. It should be permanently shelved.