It was part of the Jurong Island Healthy Lifestyle, Safety and Security Awareness Day 2009 organised by the police to test a possible plan of action should there be an emergency such as leakage of flammable material or a large storage tank fire.

The 1,400 workers staying in the dormitories belonging to petrochemical companies Exxonmobil and Shell had to walk briskly for 2km to a desiganted spot where the buses were already lined up.

Once there, they packed into 38 buses which drove them to the checkpoint about 14km away.

Jurong Island today is home to over 94 petroleum, petrochemical, specialty chemical and supporting companies with more than $31 billion in fixed assets investment. Due to the highly-flammable industries based there, it is seen as a vulnerable target to attacks.

Member of Parliament for West Coast GRC, Mr Cedric Foo, said: 'Everybody understands that the terrorist threat is something that we should not dismiss and... this exercise did help us recognise that the threat is looming.'

After the mock evacuation, the workers were able to view an exhibition on issues such as crime prevention, fire safety and health concerns.