KUALA LUMPUR, June 28 — Authorities have detected three types of flammable and toxic gases in Pasir Gudang, Johor, one which they suspect to be the main contributor to the recent complaints of breathing difficulties among nearby residents, Yeo Bee Yin said today.

The Star reported the energy, science, technology, environment and climate change minister saying the suspect gas to be methyl mercaptan while the other two gases detected were named acrylonitrile, and acrolein.

"The presence of the gas was an anomaly, and could cause adverse effects on children and those with health conditions such as asthma,” she was quoted telling a news conference in Putrajaya, referring to methyl mercaptan.

Methyl mercaptan, also known as methanethiol, is mainly used to produce methionine in industrial quantities as a dietary component in poultry and animal feed. Methyl mercaptan is also used in the plastics industry and as a precursor to manufacturing pesticides. A flammable gas, in very large quantities it is toxic and affects the central nervous system.

Acrylonitrile is used in the manufacture of certain useful plastics, and is toxic even in low doses. Acrolein is largely used to produce herbicides, and is also toxic enough to irritate the skin, eyes, and nasal passages.

Yeo said enforcement efforts are continuing, with the 250 chemical factories of the 2,005 licensed factories under observation.

"Immediate measures have been initiated by the ministry, to dispose of the factors which contributed to the presence of the gas,” she said.

Fire and Rescue Department personnel come to the aid of a student at Sekolah Menengah Kebangsaan (SMK) Tanjung Puteri Resort in Pasir Gudang June 24, 2019. — Bernama pic

In a separate report, Berita Harian quoted Yeo as blaming unsustainable development in Pasir Gudang for causing long-term harm to the environment.

"The rapid development and high concentration of chemical industries in the area are the main contributors to the environment’s loading capacity impact, affecting the air, land, and rivers.

"Such unsustainable development can cause the saturation of various gases or vapours in the air, improperly-controlled effluent release in drainage, all of which results in a sensitive and unstable environment,” she said.

Yeo added the development has also resulted in the absence of a buffer zone between chemical-based industries and school, housing and social activity centres, thereby exposing residents to the chemical risks.

"The ministry is taking several immediate steps, including the analysis of the loading capacity, and buffer zones to reduce the chemical impact risk.

"We will also create a system to determine the volume of air saturation in Pasir Gudang, via the Air Distribution method as seen in developed countries,” she said.

An automatic gas observation station will also be built to provide more efficient and faster chemical disaster warnings.

"This will enable the authorities to react more proactively, as Pasir Gudang will be the first heavy-industry area with an automatic environmental warning system in the country,” Yeo said.

Health Minister Datuk Seri Dzulkefly Ahmad, who was also present at the conference, said as of yesterday a total of 748 breathing difficulty cases were reported in Pasir Gudang. Of these, 709 were treated as outpatients and 39 required hospitalisation.