An explosion at a PVC plant in South Korea on July 3 killed six workers and injured a security guard at a factory owned by Hanwha Chemical Co., the country's largest petrochemical manufacturer.
According to local reports, the blast happened at 9:19 a.m. as welding work was being done to expand a storage tank at the factory's wastewater disposal facility.
The Ulsan, South Korea, facility, about 185 miles southeast of Seoul, is in a large industrial area and is Hanwha Chemical's second largest factory.
Local media said the cause was still being investigated but that officials suspect a welding spark ignited methane, biochemical gas or another heat source.
The English language Korea Times newspaper quoted Hanwha as saying that workers conducted a safety check and measured gas concentrations around the tank but not in the interior of the tank, which was sealed.
In an editorial, the newspaper said the industrial area where the factory sits has had previous safety problems.
“The national industrial complex that hosts the plastic plant has had many previous warnings — nearly 200 accidents in the past five years — so safety should have been a priority there for all,” the paper wrote.
“The company's explanation that it did not inspect the "completely sealed" interior of the tank may well indicate a laxity on site rather than strict adherence to the step-by-step safety rules,” it said. “The accident therefore begs the question whether proper safety measures were in place.”
Hanwha CEO Kim Chang-bum made a public apology July 3 for the deaths and explosion. Local media said executives from Seoul-based Hanwha and subcontractors were summoned by the local police on July 5, and that the investigation continues.