Nikon Corp. and temporary staff agency Atesuto were ordered to pay 24.8 million yen in compensation to a woman whose 23-year-old son committed suicide after being overworked.

The Tokyo District Court ruling on Yuji Uendan's death in March 1999 is the first such decision in Japan ordering compensation paid for "karoshi," or death from overwork, of a temp service worker, according to a group of lawyers.

Labor law experts have said that protecting the rights of temp-agency employees in their workplaces has been difficult because of their situation: They are hired by one firm to work for another.

Uendan was sent to do product-quality inspection work in Nikon's Kumagaya factory after signing up in 1997 with Nagoya-based temp-staff company Nekusuta, which later changed its name to Atesuto.

Presiding Judge Toshifumi Shibata said Uendan suffered "strong psychological pressures that could cause mental disorder, stemming from his duties and the closed nature of his work environment," and long and irregular hours.

"Both companies should have taken precautions (so Uendan would) not to be strained by too much psychological pressure," even though the employers had different contracts for him, Shibata said.

The suit was filed in March 1999 by Uendan's mother, Noriko, 56, who sought 144 million yen in compensation.

Uendan worked in a windowless "clean room" at the Nikon factory and had to wear a suit, gloves and a mask. He worked day and night shifts of 9 hours and 45 minutes each. He later developed depression and expressed a desire to quit in 1999. When he committed suicide, he had just finished working 15 days in a row.