Jurong lab blast: Ex-director pleads guilty

 The former executive director of an industrial gas supply firm linked to a 2015 fatal blast has admitted in a district court that he had failed to take necessary measures to ensure the safety of the company's employees who were working in a laboratory at its speciality gas centre.

The explosion, which ripped through Leeden National Oxygen's laboratory in Tanjong Kling Road in Jurong on Oct 12, 2015, killed chemist Lim Siaw Chian.

The incident left seven others injured.

Gary Choo Pu Chang, 64, who had initially claimed trial to an offence under the Workplace Safety and Health Act, pleaded guilty on Monday (April 25).

In January last year, Leeden National Oxygen was fined $340,000 and Mr Steven Tham Weng Cheong, who was the company's managing director, was fined $45,000, over workplace safety lapses.

The company and Mr Tham, then 69, were each convicted of an offence under the Act in December 2020.

Leeden National Oxygen was established on Oct 1, 2014, following the merger of two firms - Leeden and National Oxygen.

Before the merger, Choo was National Oxygen's deputy managing director and oversaw several departments, including the laboratory.

After the merger, he became the executive director of the new company.

Choo resigned on Aug 12, 2015, two months before the fatal blast on Oct 12 that year.

Ministry of Manpower prosecutors Samuel Chua and Khong Zi-Wei stated in court documents: "At the material time, (Ms Lim), who was employed as a chemist... was carrying out a gas analysis on a gas cylinder in the laboratory.

"The initial explosion killed (Ms Lim) instantly and injured three of her colleagues, who were also working in the laboratory. The incident further resulted in injuries to four other employees of (Leeden National Oxygen)."

Earlier, The Straits Times reported that Ms Lim had returned to work from maternity leave a week before the tragedy.

The former Malaysian had received her Singapore citizenship just a month before she died.

Her charred remains were found on six occasions over a two-month period after the incident, and were identified using her daughter's DNA. Her baby was six months old at the time.

In 2016, then State Coroner Marvin Bay found Ms Lim's death to be an industrial misadventure.

The court heard on Monday that closed-circuit television (CCTV) footage showed that the initial explosion occurred towards the rear of the laboratory.

Ms Lim was last seen touching a regulatory valve assembly (RVA) connected to a gas cylinder beside a gas chromatography machine before a bright light appeared.

The CCTV footage then went blank.

A forensic assessment later determined that the primary failure was at an unqualified welded joint found in a stem of the RVA, which was attached to a valve of the cylinder.

The prosecutors said: "The failure of the welded joint in the... stem of the RVA was found to have pre-existed but was not prudently checked before usage prior to the incident. The failure at the unqualified welded joint at the... stem of the incident RVA resulted in a leak of flammable methane-oxygen-nitrogen mix.

"The leak... led to an ignition caused by the spontaneous reaction of the leaking gas mixture in the presence of frictional heat generated due to the escaping gas mixture and internal sudden agitation of debris and particulate."

The blast happened soon after and the court heard that some of the RVAs recovered from the laboratory were later found to have been modified as well.

Among other things, Choo had failed to take reasonably practicable measures to ensure that unsafe modified RVAs were not used in the laboratory when testing combustible gases.

The court heard that he had also failed to ensure that there was a system for the tracking and maintenance of the RVAs used in the laboratory.

Choo will be sentenced this Friday.