SINGAPORE - Minister for Environment and Water Resources Masagos Zulkifli on Monday (Nov 6) set out the dos and don'ts for surviving a chemical attack, as he answered a question in Parliament about a chemical stench that engulfed parts of Singapore in September.
First, people are to leave the affected area quickly.
Those who are unable to do so should head to the nearest indoor area, shut the doors, windows and ventilation systems, and seal the gaps with masking tape.
Singaporeans can adopt such measures to protect themselves against hazardous vapours during a chemical agent attack, Mr Masagos said.
He was responding to Ms Joan Pereira (Tanjong Pagar GRC) who asked about Singapore's preparedness to deal with a chemical gas attack by terrorists.
Her question, along with those of three other MPs, was prompted by an episode on Sept 25, when a strong odour which smelled like like burning plastic, and thick smoke, was detected by people in parts of Singapore, causing anxiety.
Mr Masagos said yesterday that the National Environment Agency (NEA) had tested for hazardous vapours in the air and found that it was within safe limits. Air quality was also found to be satiafactory.
With the help of the Malaysian authorities, the NEA later identified the source of the smell as a chemical plant in Pasir Gudang, an industrial estate in Johor located a little more than 1.5km across the Strait of Johor from Punggol.
Controlled burning to get rid of waste gases is a common occurrence there, and was thought to be the source of the chemical stench.
Mr Masagos said: "A stop work order was issued against the operator... and the operator was required to carry out a list of remedial actions."
Some people living in the affected areas had complained that they were not updated qucikly enough about whether the gases were dangerous, and raised concerns about whether Singapore was prepared to handle terror attacks in which chemical gases are used.
Mr Masagos assured Ms Pereira that agencies such as Singapore Civil Defence Force (SCDF) and NEA are prepared to handle terrorists who use chemical gases.
For example, the SCDF regularly tests its responders by conducting simulations. They are also equipped with portable sensors to detect and identify toxic gases, including chemical warfare agents, in the air.
The NEA, meanwhile, maintains a network of real-time air quality monitoring stations across Singapore to detect air pollution. A number of these stations can measure low levels of Volatile Organic Compounds (VOCs) in the air.
Such vapours, which can cause smells by themselves or when they react with other substances, can come from both man-made and natural sources.
When smells or gases are detected such as during Sept 25, the agency also deploys officers, equipped with portable instruments, to affected areas to measure the levels of chemical compounds in the air.
Ms Sun Xueling (Pasir Ris-Punggol GRC) asked about the long-term effects of breathing in low levels of VOCs in the air.
Mr Masagos said that studies on safety thresholds of most VOCs are available "only for occupational exposure" where workers are exposed to at least around eight hours of hazardous levels.
He added: "Studies which are connected with low, constant exposure... are not yet available or not been done, so we can't rely on such reports to produce any guidelines for our authorities to implement."