A worker at a leather factory jumped into a pit of toxic wastewater to save his colleague, but ended up dead himself, a coroner's inquiry heard yesterday.
Nam Heng Leather Dyeing partner and factory boss Ang Keat Hong was giving his view of the video footage of the incident on Dec 26 last year that claimed the lives of Chinese nationals Yang Zhonghua and Zhai Hailei.
He said: "I caught a glimpse of (Zhai's) shadow... I noticed him removing a plank and voluntarily jumping in."
The 3m pit was directly under a water treatment unit. Known as a sump, it was filled with wastewater 2.5m deep at the time.
The water contained chemical by-products from the leather tanning process, and had passed through a basket secured just above the sump.
Mr Yang, 37, was asked to retrieve the basket and clean it of filtered residue - a routine task that should take less than a minute, Mr Ang told the court.
But he likely had to squat or kneel in the cramped space before reaching to get it.
This was when Mr Yang fell through a gap measuring 1.2m by 34cm.
Mr Zhai, 26, went in search of him after he had not returned nearly 10 minutes later.
Both men were eventually found in the sump and pulled out, but died in hospital on Jan 4 after spending almost 10 days in a coma.
The two workers each left behind a wife and two young children.
The company had no relevant safety protocol in place at the time as it was "highly unlikely" that workers tasked to retrieve and clean the basket would fall through the gap, Mr Ang said.
Ministry of Manpower (MOM) investigation officer Mark Eugene Han testified yesterday that the two men could have been overwhelmed by hydrogen sulphide in the air, before falling into the sump.
The gas is associated with the production of leather.
Depending on its concentration and the length of exposure, it can cause symptoms including dizziness and respiratory failure.
Mr Han and Mr Ang disagreed on how much of the poisonous gas had been in the air at the time at the factory located on Tai Seng Avenue, in Ubi.
MOM's final investigation report on the matter is still pending.
The hearing before State Coroner Marvin Bay resumes on July 10.