March 28 (Bloomberg) -- Mori Building Co., which owns the Roppongi Hills complex in Tokyo, said revolving doors there, including the type that killed a six-year old boy on Friday, have caused 32 other accidents since the complex opened last April.

``In total, there were 32 other accidents involving revolving doors since the opening,'' said Keiko Horioka, a spokeswoman at Mori Building, confirming media reports by newspapers such as the Asahi and Nihon Keizai.

Ryo Mizokawa, from Osaka Prefecture in western Japan, died on Friday after his head became trapped in a revolving door at a second-floor entrance to the Mori Tower building at the complex, the property developer said on its Web site.

The boy's death was caused by cerebral damage from the impact of the door which trapped his head, the Asahi said, citing the results of an autopsy ordered by the police yesterday.

Police are investigating whether the boy's death was caused by negligence, which may warrant a charge of involuntary manslaughter, state-run NHK television said yesterday.

The company said at a news conference on March 26 that only two other confirmed accidents, involving revolving doors, occurred at the complex since its opening, the Asahi said.

``Before the accident on March 26, we didn't keep those kinds of statistics,'' Hiroo Mori, a managing director at Mori Building, said at a news conference yesterday, the Asahi reported. ``This is the first time we've put any together.''

President Minoru Mori, in a release on the company's Web site, said he ``deeply apologized'' for the boy's death. Prime Minister Junichiro Koizumi inspected the site of the accident today and offered flowers in condolence, the Asahi said.

First Accident

The company said the first accident occurred the day after Roppongi Hills opened in April, the Asahi reported.

Twelve accidents involving the same type of revolving door that trapped and killed Mizokawa have occurred at Roppongi Hills in the past year, said Mori Building's Horioka.

Mori Building said of the 12 people involved in accidents, seven became stuck in the revolving doors and three had to be taken to the hospital by ambulance for treatment after suffering serious injuries. The company also said 20 accidents have occurred involving smaller, hand-pushed revolving doors.

Mori Building said it asked Sanwa Shutter Corp., the supplier of the revolving doors installed in Roppongi Hills, to reduce the blind spots in the door sensors that are used to detect motion, after discovering blind spots existed when another child was caught in a different door in December, Asahi said.

Won't Halt

Mori Building didn't take any additional safety measures at the time because Tokyo-based Sanwa Shutter said that widening of the sensor's range would cause an increase in the number of times the doors would mistakenly stop, Asahi reported.

Sanwa Shutter said at a news conference yesterday that the type of revolving door involved in the fatal accident won't halt immediately after the sensor is activated and may continue to rotate as much as 25 centimeters (9.8 inches), NHK said.

In all, eight revolving doors of the type that killed Mizokawa are installed at the complex in addition to 37 smaller revolving doors that need to be pushed by hand, the Asahi said.

Mori Building generates about 40 billion yen in annual revenue from commercial facilities at the Roppongi Hills complex, the Nihon Keizai reported today.

The $2.2 billion Roppongi Hills complex includes a 380-room Grand Hyatt hotel, a Virgin Group movie theater complex and 4 million square feet (372,000 square meters) of office space that houses brokerages such as Goldman, Sachs & Co. and Lehman Brothers.

Mori Building is Japan's biggest private developer. Sanwa shutter shares fell 14 yen, or 2.2 percent, to 619 on Friday.

To contact the reporter for this story: Michael Tsang in Tokyo at mtsang1@bloomberg.net.

Last Updated: March 28, 2004 00:37 EST