Plant lacked permits for liquid ammonia

The cold storage plant where 15 workers died in a liquid ammonia leak was not permitted to use the coolant, Shanghai's work safety watchdog announced Wednesday.

The fatal leak, which left 25 others injured, occurred around 10:50 am Saturday at Shanghai Weng's Cold Storage Co, a company in Baoshan district that specializes in frozen food processing, transportation and storage. The leak was caused by loose pipe fittings.

National regulations require plants to obtain permission from local work safety authorities if they use more than 360 tons of liquid ammonia each year.

Although it is unclear how much liquid ammonia Weng's Cold Storage used each year, its refrigeration system can hold up to 86 tons of the coolant, according to the Shanghai Administration of Work Safety.

Liquid ammonia is not commonly used in the cold storage business because it is dangerous, said Cen Jianrong, manager of Shanghai Wusong Luoji Cold Storage Co, another frozen food plant in Baoshan district. Still, some companies use it because it is cheaper than other more commonly used coolants.

Employees who work with liquid ammonia are supposed to receive special training, Cen told the Global Times.

Liquid ammonia transforms into a gas when its temperature rises above -33.34 C.

As a gas, it is highly caustic, said He Heyong, a chemistry professor at Fudan University. It will burn exposed skin. If inhaled, it will severely damage the lungs.

Most of the injured workers suffered burns to their skin and respiratory tracts, according to a report on the news website eastday.com. The workers who died suffered facial burns so severe that it was difficult to identify them.

Inspections also uncovered a food processing workshop that had been added on to the plant after it was first built.

The workshop occupied the fire escape passage, according to the Shanghai Administration of Work Safety. The plant's owner designed the workshop and hired unqualified workers to build it. The employees who worked there had not been trained.