"Don't wait for concrete evidence to prove whether toxic agents are the culprits behind the sicknesses or deaths. If you find pollution is higher than safety standards, just quickly reduce it," said Dr Chatchai Ekpanyaskul, an occupational diseases expert from Srinakharinwirot University's Faculty of Medicine.

Chatchai said doctors could only show the association between pollutants and cancer, but could not prove pollutants caused cancer.

"If you allow the pollutants to be in the environment, it means you give it time to kill people," he said.

The Pollution Control Department (PCD) has found 40 volatile organic compounds, including 19 cancer-causing agents, contaminating the air at a higher level than the safety standard of the US Environmental Protection Agency.

The agents included suspected human carcinogen Acrolein, Trichloroethylene which cause cancer of the liver, non-Hodgkin's lymphoma, cervical cancer and leukaemia, and benzene, cancer-causing agents for various types of leukaemia. Power plants at Map Ta Phut were also found to have emitted sulphur dioxide beyond safe levels. The gas causes respiratory problems.

The National Cancer Institute (NCI) found a high rate of new cases of cancer in Rayong province, with Muang district - where the industrial complex is situated - having the highest rate of cancer among the province's eight districts.

The NCI survey, conducted from 1998 to 2000, found that in Muang 189.7 males in every 100,000 were diagnosed as having cancer, while the ratio among females was 183.4 in every 100,000.

There were also three other districts with a high rate of cancer cases. Klaeng, Ban Khai and Wang Chan are located to the northeast of Muang district.

 Anond Snidvongs, an oceanologist from Chulalongkorn University, said that as a Gulf coastal province Rayong faced north and northeast-bound monsoon winds eight months a year.

"Logically, airborne pollutants would spread in the same direction as the winds," he said.

On January 11, the PCD asked the National Environmental Board to declare Map Ta Phut industrial complex, which comprises four industrial estates, as a pollution-control zone under the 1992 Environmental Protection Act.

Such a declaration would allow the PCD to control emission levels of factories within the zone, while the area could not be used for a third phase of petrochemical-industry development as planned.

The board, chaired by Deputy Prime Minister and Industry Minister Kosit Panpiemras, rejected the proposal and set up two subcommittees to study the relationship between illnesses and pollutants. Kosit said he gave the factories one year to curb toxic emissions, otherwise he would declare it a pollution-control zone.

Uthai Janthima, governor of the Industrial Estate Authority of Thailand, welcomed the board's decision.

"To declare a pollution-control zone without concrete evidence will cause damage," he said recently during a meeting with representatives of Map Ta Phut communities.

But the decision upset people involved in public health.

"The association between people's sickness and the toxic agents is so clear. The point is whether you want to accept it or not," said Sunantha O-siri, manager of the Eastern Health System Research Management Centre. 

Pennapa Hongthong

The Nation