Eight years after the world's worst nuclear accident at Chernobyl, it is still too soon to react to any mishap at a nuclear installation in the former Soviet Union with anything but alarm.


This week0's fire at the giant Mayak nuclear reprocessing plant in the Urals mountains may not turn out to have been serious -- officials at the plant are adamant that the fire was put out within minutes and that the amount of radioactive gases that escaped into the atmosphere too small to be of significance.


But the nuclear industry the world over -- whether at Chernobyl, Sellafield or Three-Mile Island -- has a history of playing down accidents and leaks, just as environmental groups can be relied upon to talk up the danger of such incidents.


In the case of the Mayak plant -- which has had a history of accidents since it was built in the late 1940s to make plutonium for bombs -- when two groups of Russian officials come out with contradictory risk assessments, it is even more disturbing.


While Nuclear Power Ministry officials were insisting that the fire was minor and that there had been no serious contamination, a spokesman for the state's nuclear inspection agency described it as very grave and gave it three points on a seven-point nuclear disaster scale.


Whom is one to believe?


It is impossible to forget that while the Chernobyl reactor No. 4 was spewing a radioactive cloud over Europe in April 1986, the first priority of plant officials was a cover-up -- even to the extent of delaying the evacuation of nearby villages lest the story got out.


True, times have changed, but old habits die hard. And nowhere harder than among old Soviet bureaucrats, who still occupy positions of power and influence in the new Russia.


The Mayak complex is situated in one of the most polluted regions of Russia, where contaminated rivers and lakes now threaten the entire water system of the region. Serious accidents occurred there in 1957 and 1967, in both cases releasing radioactive particles in the surrounding countryside.


In recent years, a reported relaxation of safety measures in the nuclear industry as a whole -- due to financial strictures -- have undermined confidence even further. On the positive side, news of Wednesday's fire spread fast, while it took years for reliable information about the previous accidents at the plant to emerge.


Accidents will happen, whether in Russia, the United States or anywhere else. But especially here, squabbles of the kind at Mayak this week leave any Russian resident wondering who will know and who will tell the truth if a serious accident should occur.