Motorists kept their distance as rescue teams wearing hazmat suits descended on Tuas Second Link yesterday morning to "contain" a chemical spill at the site.
The emergency drill, designed to test the response in the event of an accident, involved a lorry carrying drums of hydrochloric acid and a tanker filled with ammonia gas.
Conducted as part of the bilateral cooperation programme under the auspices of the Malaysia-Singapore Joint Committee on the Environment, the exercise was the 12th drill since 2000 to test the effectiveness of an emergency response plan jointly developed by Singapore's National Environment Agency (NEA) and Malaysia's Department of Environment (DOE).
The drill began with the Singapore Police Force being notified of the accident at 10am, kick-starting a series of events involving agencies from both countries responding to the emergency.
There were two designated casualties at the accident site - an unconscious lorry driver, who had apparently suffered a heart attack, and the tanker driver, who had collapsed on the road after inhaling toxic fumes.
A total of 11 agencies and 150 personnel from both countries were involved in the exercise.
Stressing the drill's importance, NEA chief executive Tan Meng Dui said: "The continued success of this collaboration highlights the commitment of agencies from both countries to ensure a prompt and effective response to any chemical spill incident in Tuas Second Link.
"It also serves to improve mutual understanding and get both sides used to working together to address any incidents with potential environmental impact."
The hour-long drill ended with the casualties safely evacuated and the affected area decontaminated.
DOE director-general Norlin Jaafar said that rescuers and agencies from both countries were able to work as a team.
She said that the drill was initially a "tabletop" exercise but has since been conducted with more realism on the ground.
Ms Norlin has fully supported the exercises conducted over the years.
She said: "This is to enhance the coordination between the two countries regarding the emergency response procedures, and to allow early notification on any incident involving vehicles transporting chemicals on the second crossing."
Each year, about 160,000 tonnes of hazardous chemicals are transported between Malaysia and Singapore via the Tuas Second Link.
So far, there has been no chemical spill in the area.