Black smoke rises from burning flames at a Nippon Shokubai Co. chemical plant.
Photo credit: AP Photo/Kyodo News
HIMEJI, Hyogo--Authorities inspected the site Sunday of an explosion at Nippon Shokubai Co.'s plant in Himeji, which killed a firefighter and critically injured a company employee the day before.
Also Sunday, the Aboshi Police Station raised the number of those injured in Saturday's incident to 35 as five more firefighters were found to have sustained light injuries. The cause of the explosion is unclear, according to the company.
The Hyogo prefectural police are interviewing plant workers and others as they suspect the explosion was due to the company's professional negligence resulting in death and injury.
Nagahiro Yamamoto, a 28-year-old firefighter, is believed to have been burned to death after being exposed to high-temperature chemicals, which sprayed from a chemical tank that exploded. The blast also left company employee Kenji Miura, 31, of Taishi, Hyogo Prefecture, in critical condition, the police said.
Three fire engines were damaged in the incident, they added.
The Fire and Disaster Management Agency and the Hyogo Labor Bureau were investigating the site of the accident Sunday.
According to the city's fire department and other sources, a 5.6-meter-high acrylic acid storage tank with a diameter of 4.2 meters exploded at 2:35 p.m. Saturday when the company's fire crew members were spraying water on it. The tank that exploded is one of three contiguous tanks, and is the most southerly of the three. Following the explosion, the blaze apparently spread to the other two units.
Shortly before 1 p.m., a company employee reportedly discovered the temperature inside the tank was rising abnormally, prompting the in-house fire crew to spray water over the unit. However, the temperature did not fall.
At 1:51 p.m. the company called the fire department, saying dangerous chemical reactions could occur. At 2:05 p.m. the first batch of firefighters arrived at the plant. About 30 minutes later, the explosion occurred as they were preparing to spray down the tanks.
At that time, Yamamoto was reportedly trying to connect water-supply hoses for the operation, and was standing near a fire engine about 20 meters west of the tank that blew up.
About 50 to 60 employees and others were at the plant when the tank exploded.
Asked whether firefighting operations were carried out appropriately, Katsumasa Nakagawa, a deputy chief of the city's fire department, said at a press conference Saturday night, "As the city fire department didn't spray water before the explosion, we'll investigate the situation thoroughly."
But he speculated the explosion occurred because the temperature inside the tank climbed faster than expected.
According to the chemical company, to lower the temperature inside the tank, it usually reduces the level of oxygen by injecting nitrogen. The police will probe whether nitrogen was actually injected into the tank and why the temperature rose.
Nippon Shokubai Co., based in Chuo Ward, Osaka, is the world's third-largest maker of acrylic acid, producing about 62 tons of the chemical annually, of which about 46 tons are manufactured at the Himeji plant.
Nippon Shokubai held several press conferences at the plant Saturday. At the first briefing, Yoshito Kawasaki, manager of the company's general affairs section, said, "We are sorry for causing this situation."
Asked about the cause of the explosion and the status of the site, he responded by making such remarks as "We don't know," and "We'll find out more by the next press conference."
The company, which was formerly named Nippon Shokubai Kagaku Kogyo, suffered a similar tank explosion in March 1976.
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