The EPA released the report at a workshop held to assess the overall industrial evaluation of the FPG's naphtha cracking complex since its inception 10 years ago.

The report showed that although Chiayi County and City as well as Tainan County and City are farther away from FPG's naphtha cracking complex than Yunlin and Changhua counties, the four counties and cities have suffered more from toxic air pollutants generated by the cracking plants than the latter two counties.

Yen Yeou-li, an associate professor with the Department of Safety, Health and Environmental Engineering of the National United University in Miaoli County, said that ozone from volatile organic compounds discharged from factories in the FPG petrochemical complex have been carried to the southern counties of Chiayi and Tainan.

Citing the results of a quantitative study conducted between 1994 and 2009, Yen said the ozone density monitored in Chiayi's Singang Township has been as high as 221 parts per billion (ppb), much higher than the allowable level of 120 ppb.

The ozone density monitored in Tainan City and County is also higher than that found in Yunlin County and neighboring Changhua County, said Yen. Ozone can cause coughing and allergies, Yen said.

Meanwhile, the density of sulfur dioxide in the air at Yunlin County's Taisi Township has been found to be exceptionally high and complaints lodged by local residents have also increased noticeably since the petrochemical complex was built, Yen noted.

FPG said Thursday that it would not comment on the discussions at the workshop until the two-day session ended.

The Chiayi County government said it was paying close attention to the workshop and the discussions. If finances permit, the county government will launch a health risk assessment drive in the county, it said.

In related news, Economics Minister Shih Yen-shiang said yesterday at a legislative hearing that the Ministry of Economic Affairs (MOEA) will wait for the final result of an environmental impact assessment before deciding whether to change the site of the controversial Kuokuang Petrochemical Park.

Shih noted that the site of the proposed park has been changed a number of times, with the location last shifted from Yunlin County to Changhua County, based on a proposal by the Changhua County government.

The project involves building the country's eighth naphtha cracker on a plot of tidal land in Changhua's Dacheng area.

Shih stressed that if the project is scrapped, Taiwan's self-sufficient ratio for ethylene — a substance used for manufacturing plastics and other chemicals — will decrease.

This could lead to an exodus of Taiwan's petrochemical midstream and downstream operations because it is difficult to import ethylene from other countries, the minister said.

Environmentalists have expressed strong opposition to the plan, arguing that the facility would cause irreversible damage to local flora and fauna, endanger marine life, and ultimately threaten the livelihoods of local farmers and fishermen.

Tsai Chia-yang, president of the Taiwan Environmental Protection Union's Changhua Division, said at the hearing that it is a mistake to try to build a petrochemical park at one of the country's most important agricultural and fishing capitals. The designated site is also home to a major wetland of great conservation value, Tsai pointed out.