THE toxic gas and chemicals poisoning incidents in Johor highlight the dire need for an urgent review of the practices and regulations of managing chemicals in Malaysia.

Both the Sg Kim Kim incident in March 2019 that affected 5,000 schoolchildren and the Pasir Gudang incident in June 2019 that affected 1,178 schoolchildren in the same area, had shocked the nation. In the Pasir Gudang incident, only schoolchildren in the third and fourth floors were affected. The toxic gases detected in the first incident were acrylonitrile, acrolein, and benzene but in the second incident, methyl mercaptan was also detected.

Initially, the Department of Environment concluded that the source of the first incident was the chemical dumping in Sg Kim Kim but the river was clean at the time of the second incident.

Recognising the urgent need for an independent investigation of the two incidents, the then Energy, Science, Technology, Environment and Climate Change Ministry (Mestecc) had engaged the Academy of Sciences Malaysia (ASM) to conduct investigations into both incidents and to propose recommendations for actions to be adopted by the ministry.

The ASM task force hypothesised the toxic gases could not have come from the ground since slow evaporating, heavier than air, chemical vapours with negative buoyancy would remain on the ground and hit the lower floors. The toxic gases could only have come from the tall stacks of the chemical factories in Pasir Gudang since the high velocity gas discharges would have enough momentum to carry the negatively buoyant gas plumes to the schools and still hit the upper floors.

The task force back-tracked gas concentration measurements to their possible sources using a Gaussian dispersion model for gas released from a tall stack and real time meteorological data. The frequency density distribution of their locations generated by the analysis led the task force to conclude that the most likely locations of the sources of the toxic gases emission during both incidents were at the two main chemical industry areas of Pasir Gudang.

The task force also found no evidence the toxic gases were emitted from either the chemical waste dumped into Sg Kim Kim in the first incident or from chemicals waste stored in open drums after removal from the river in the second incident.

The task force had proposed several recommendations for the short, medium and long term to ensure incidents like these never happen again in the future, some of which had been adopted by the then Mestecc.

These recommendations could also serve as benchmarks for best practice in chemical management at other industrial areas nationwide in the near future.

In the short-term, the task force had proposed installing better instruments to measure multiple toxic gases such as a Gas Chromatography Mass Spectrometry (GCMS) on site for closer monitoring; installing more toxic gas detectors around Pasir Gudang to serve as early warning system; setting up an onsite DoE office on in Pasir Gudang for stronger enforcement of environmental laws and regulations and lastly implementing better methods of assessing the severity of the adverse effects of multiple toxic gases since exposure to multiple chemicals simultaneously may have additive or synergistic toxicity.

In the medium-term, the task force had recommended broadening the definition of “pollution” in the Environmental Quality Act 1974; reclassifying all Environmental Hazardous Substances (EHS) as “pollution” and determining their acceptable conditions to strengthen prosecution of air pollution cases involving toxic gases; amending the definition of EHS under the Act based on both intrinsic hazardous chemical characteristics and the Multi-lateral Environment Agreement list; amending the Occupational Safety and Health (Classification, Labelling and Safety Data Sheet of Hazardous Chemicals) Regulations 2013 to ensure that chemicals obtained through local suppliers in the circular economy must be reported in the Chemical Information Management System (CIMS) and lastly, increasing the minimum buffer zone distance between chemical factories and residential areas to between 1,000m and 1,500m.

In the long-term, the task force had proposed integrating the CIMS under the Department of Occupational Safety and Health and the EHS Notification and Registration System under the DoE; establishing the Chemicals Management Commission, a statutory body to govern chemicals management and implementing Integrated Water Resources Management or the Integrated River Basin Management to ensure water governance is optimal.

To read the full report, please click here. – April 5, 2021.

* The Academy of Sciences Malaysia, under the purview of the Science, Technology and Innovation Ministry, is committed to enhance the scientific capacity of the country.

* This is the opinion of the writer or publication and does not necessarily represent the views of The Malaysian Insight. Article may be edited for brevity and clarity.