Sunday, October 3, 1999 Published at 08:04 GMT 09:04 UK
Nuclear accident plant broke rules
Monitors are still checking the area for contamination
The operator of the plant where Japan's worst nuclear accident happened on Thursday has admitted using illegal standards for uranium processing for the past four years.
Instead of relying on high-tech equipment, it allowed workers to transport uranium in stainless steel containers similar to buckets.
Experts said the violations provided an example of the facility's insufficient attention to safety.
The revelation adds to the catalogue of incompetence and lax standards being uncovered by the investigation into the accident.
It has also been reported that the workers had never received proper training.
Hideki Motoki of the Tokyo-based JCO said that the company knew its standards did not meet legal requirements, but it was not certain whether the violations had caused the accident.
He said more explanation was needed from workers who were involved in the accident and who are still in hospital.
Police are now investigating JCO and its employees on suspicion of professional negligence.
However, BBC Japan Correspondent Juliet Hindell says the government's supervision of the nuclear fuel industry is certain to come under scrutiny.
The accident happened after workers allegedly mixed too much uranium in a tank, setting off an uncontrolled atomic reaction which pushed radiation levels around the building to 15,000 times above normal.
Three workers were seriously injured by exposure to radiation, with two still said to be in need of bone marrow transplants.
Media reports also said that one of the workers had been exposed to far higher levels of radiation than hospital officials had initially reported.
More than 50 people were treated for radiation exposure after the accident - about 45 plant workers, three fire-fighters and seven people working at a nearby golf course.
On Saturday, the government offered health checks to people living within half a kilometre of the site.
Farmers have been warned not to harvest their crops until safety checks had been carried out.
Japan has 51 commercial nuclear power reactors, providing one third of the country's electricity.
The Vienna-based International Atomic Energy Agency says the situation is more serious than first thought, but its offer to send a team of experts has been declined.