PASIR GUDANG (Malaysia)/ JOKHABAD (India) • When local investigators scoured the river bed of Sungai Kim Kim in Johor for clues in a chemical dumping case that hospitalised more than 1,000 people in March, they found a cocktail of toxins, including a colourless liquid commonly secreted when tyres are recycled.
That led the authorities to a small company called P Tech Resources, which is involved in pyrolysis. It burns old tyres to make low-grade oil which industry sources say is also common elsewhere in South-east Asia, China and India.
Police have charged a lorry driver and all three of P Tech's directors over violation of a law prohibiting the illegal dumping of waste. They have all denied wrongdoing.
Done properly, in a controlled environment, tyre pyrolysis has been lauded by the recycling industry as a green way of turning a complex waste into a useful energy source.
Tyres are heated in the absence of oxygen and the gases released are condensed into a low-quality oil that can be used in asphalt or fuel oil, depending on its purity.
During a visit to P Tech premises, Reuters found piles of tyres bound in bales, a tall chimney and a filthy pond behind closed gates.
Neighbouring workers said the firm operated at night and its work produced a stench that would linger until the morning.
"Tyre pyrolysis is not a problem. The problem is with the mismanagement of it," said Malaysian Environment Minister Yeo Bee Yin, when asked about the pyrolysis industry.
Malaysia's Department of Environment said 22 tyre pyrolysis firms across the country are licensed, but declined to comment on unlicensed operators.
Last month, Reuters visited a cluster of about 10 tyre-burning factories in an industrial area in Jokhabad, a town on the outskirts of India's capital New Delhi.
Mounds of black powder lay on open ground at the first plant, as about half a dozen workers wearing no protection - some barefoot, their clothes and skin stained black - milled about.
At a second plant, supervisor Manoj Kumar said he was producing oil mainly used as tar for road construction.
A report commissioned by Indian environmental rights group Safe last year said that at one site in Jokhabad, carbon fumes and sludge were so bad that monkeys in the area had black faces and fur.
There is no official data on the size of the pyrolysis business. But with free raw material - used tyres - and demand for unconventional oils increasing for things including tar to build roads and fuel for ships, pyrolysis can be a lucrative business even on a small scale.
Asphalt currently sells for about US$100 (S$137) a tonne, while fuel oil sells for about US$400 a tonne.