ST. PETERSBURG, Russia - An explosion at a Russian nuclear power plant complex killed one worker and badly hurt two others, but Russia's nuclear agency said Friday no reactors were affected. The Rosenergoatom agency said radiation levels remained normal as the reactor in that part of the Leningrad nuclear plant was undergoing repairs and was not in operation. But Thursday's blast threw a spotlight on what environmentalists called uncontrolled operations at Russian nuclear sites. The blast happened in a smelter at the plant in the closed nuclear town of Sosnovy Bor, 50 miles west of the northern city of St. Petersburg. The smelter is operated by Ekomet-S, a company reprocessing scrap metal. "The enterprise ... functions illegally because there was no mandatory (state) environmental impact assessment on its construction," Dmitry Artamonov, head of the St. Petersburg branch of Greenpeace, told The Associated Press. He said Greenpeace had complained against Ekomet-S to the Sosnovy Bor prosecutors' office but it took no action. The nuclear plant has four units, or reactors, in all. Rosenergoatom said that the smelter was on the grounds of the plant's second unit, and plant spokesman Sergei Averyanov said it was about half a mile from the reactor. Oleg Bodrov, a physicist who heads the Green World ecological group in Sosnovy Bor, said that the reactor was only some 700 yards from the smelter, which is about 50 yards from a liquid radioactive waste pond. A 33-year-old worker died of his injuries Friday morning, and two others were injured, Yuri Lameko, chief doctor of the Sosnovy Bor hospital, told the AP. "There were no violations of safety levels and operating conditions of the energy units of the Leningrad nuclear plant," Rosenergoatom said in a statement. The second unit had been shut down for planned major repairs in July, it said. The plant spokesman, Averyanov, said that the blast had caused molten metal to spurt out of the smelter. Usually Ekomet-S reprocesses scrap with low levels of radioactivity, but on Thursday the metal was clear of radiation, Averyanov said. He blamed the blast on violations of technical and production rules. Bodrov said Ekomet-S began operating two years ago and was in violation of the law since it had undergone no state environmental impact assessment. When the firm was founded, the only environmental monitoring laboratory in the town of 65,000 was shut down for lack of funding, he said. "There is no independent environmental monitoring in the nuclear city of Sosnovy Bor," Bodrov said. He said this was the second accident to occur at Ekomet-S. The first happened in summer 2003, injuring some workers. In March 1992, an accident at the Sosnovy Bor plant caused radioactive gases and iodine to be leaked into the air, according to nuclear watchdog groups. One of the reactors at the 30-year-old plant is of the same type as the one at the Chernobyl nuclear power plant that exploded in Soviet Ukraine in 1986 in the world's worst nuclear accident. The station is the main supplier of electricity to St. Petersburg, and there are plans to transport some of its power to Finland. Sosnovy Bor, a center of nuclear technology, was founded 25 years ago and has 60,000 people. In addition to the nuclear plant, the town is home to a regional radioactive waste reservoir, and an experimental laboratory and training center for nuclear submarines. Almost everyone in Sosnovy Bor, which means Pine Forest, is connected with nuclear technology, and most are not native to the region. In an unrelated development, Chechen prosecutors said they have opened a criminal investigation into the improper storage of radioactive waste by a state-owned company, Prosecutors said a "catastrophic radioactivity situation" had developed at the Grozny Chemical Factory in the breakaway province in southern Russia. Grozny is Chechnya's capital. Radiation levels at one storage center at the plant are 58,000 times higher than normal, the Russian Prosecutor General's office said Friday. "It's a threat to the population because the leadership of the plant is taking no steps whatsoever to remove the radioactive material or isolate access to the plant," Chechen Prosecutor Valery Kuznetsov said.