MOSCOW. (RIA Novosti commentator Tatiana Sinitsyna). When the Chernobyl nuclear power plant's No. 4 unit exploded at 1.23 a.m. on April 26, 1986, the workers on duty in the control center were the first to suffer.

The skin of those who survived the initial explosion is said to have peeled off with their clothes.

The Chernobyl disaster affected millions of people and shocked the entire world. Radiation contaminated thousands of square kilometers and inflicted tremendous material losses. The most terrible nuclear disaster in history spread fear all over the world. In fact, mankind is yet to overcome this fear.

What is happening today in Chernobyl? Nineteen years ago, tens of thousands of people risked and sometimes lost their lives, working on a sarcophagus to enshroud the reactor. Is it still safe? "Unfortunately, it is not reliable," Dr. Alexander Borovoi, the head of the Kurchatov Institute's expert group in Chernobyl, says. "That sarcophagus conceals 185 tons of nuclear fuel with a total radioactivity of 16 million curies. Three to 5% of the fuel was scattered over adjacent territories. Thirty percent of the cesium vaporized, and the wind spread it substance over thousands of kilometers. Cesium has a half-life of 30 years. Plutonium has a 24,000-year half-life, which means Chernobyl's radiation wound will scar the Earth for an eternity."

Borovoi described how Shelter No. 1, as physicists call the 25-story structure, contains a thousand damaged rooms inside. The radiation levels total tens of thousands of roentgen per hour, which would kill anyone in just a few minutes.

No one had any experience of clearing up such major disasters before Chernobyl. Hiroshima and Nagasaki were incomparable both in terms of the causes of the tragedies and the radiation emitted. Split-second decisions had to be made, while clean-up workers had to act by trial and error, sacrificing their health.

Borovoi says the shell itself is no longer reliable, as water seeps through numerous cracks when it rains before dissolving radioactive substances that, in turn, mix with subterranean waters. Mistakes were made because remote-controlled systems were used during clean-up operations. The cracks now have a total area of several hundred square meters, which means plutonium dust could spew out, affecting thousands of on-site workers. The plant is officially closed, as the last reactor was shut down three years ago, even though it takes decades to decommission nuclear units.

Borovoi is worried because the sarcophagus stands on old structures that were damaged by fires and explosions. If the structures collapse, clouds of radioactive dust will appear. "This is a real tragedy because we gave our health and lives to Chernobyl," Borovoi said. "We tamed the 'dragon' in 1986, but now it is back to haunt us. It seems that all our work was in vain."

The international community stepped in to rectify the situation and to finance the shell's construction. In 1997, the G7 set aside $760 million for the project. Ukraine is spending this sum little by little. There are plans to build a huge metal and reinforced concrete arch near the reactor, which will eventually be placed over the sarcophagus, protecting the reactor even more effectively. "But after providing the money, the international community did not worry about how to organize the work in the most effective manner," Borovoi said. "Major international companies with no experience of work in Chernobyl repeatedly won tenders. It took them three years to accomplish what the Kurchatov Institute's experts could have done in a year. We offer cheaper and better services." This project received better top managers some time later, with the appointment of Charles Hogg, a retired U.S. naval officer, and a talented and dedicated professional, to head the group.

Nineteen years have passed since the Chernobyl disaster. People still ask how it could have happened. Experts are the only ones who know the answer. A young woman from the Kiev control center phoned Chernobyl at 2.00 p.m. April 25, telling local power workers not to reduce the fourth reactor's capacity and to delay subsequent reactor tests. She was, of course, merely conveying official orders. The plant's personnel complied and the reactor operated for another nine hours. This dangerous regime was the first step toward disaster. The "imperfect" reactor exploded, thereby exposing the personnel's mistakes.

However, a Chernobyl-type disaster is impossible today. Russian specialists have developed numerous safety systems for nuclear reactors that the human factor will never overcome.