The protest over a PX chemical plant by residents of Maoming, Guangdong province, shows that local authorities need to encourage public involvement in decision-making - particularly since PX represents a low risk to humans, experts said.

Xia Zhaolin, a professor of toxicology and a researcher on the effect of benzene on health at Fudan University, said he is surprised by the public's fear of PX - short for paraxylene, a basic material used in the manufacture of polyester and plastic bottles.

"My research area is the impact of chemicals on workers' health, and PX is not even a subject that interests me," he said.

"In real experiments, an animal would have to take in a massive amount of PX to reach levels that would result in death," he said.

Xia added that he believes the public's worry about pollution during the production process is also unfounded.

"The country is producing large amounts of other chemicals that are far more toxic than PX, such as benzene and chloroethylene," he said. "The reason PX is being singled out and has ignited such large number of protests is that the government lacks trust from the public."

The news office of the Maoming city government said in a statement on Sunday night that the local authorities will not undertake the manufacture of paraxylene until they have won the consent of the public.

The office said that it hoped the public will not be "taken advantage of" by individuals with illegal intent, and that people will help to maintain social order.

The protest over the proposed PX plant in Maoming started on March 30 and escalated as residents clashed with the police, who investigated 44 people and detained 18 for disturbing social and public order. It followed a number of similar protests over proposed PX production in other Chinese cities, including Xiamen, Dalian, Ningbo and Kunming.

"Again there was clear lack of effective communication between the authorities and the public," said Shan Guangnai, a researcher in sociology with the Chinese Academy of Social Sciences who has studied "mass incidents".

Shan said the lesson from the protest in Maoming is that the government should involve the public in the decision-making process, providing equal access to information in the government's possession.

However, Shan said, an aggressive push for GDP growth is evident in the incident in Maoming, which only increases discomfort among members of the public.

After the protest, an intense debate flared in online forums, with some entries claiming that paraxylene posed a high risk to humans. An entry on Baidu Baike, a collaborative Web-based encyclopedia provided by Chinese search engine Baidu, was revised 36 times by different contributors.

Some chemistry majors from Tsinghua University attempted to correct errors when they noticed that the toxicity descriptions of paraxylene had been altered from "of low toxicity" to "highly toxic" in entries by some Internet users.

"We tried to revise the entry because we wanted to guard the truth, not to get involved in the protests or the incident," said Wang Runjia, a sophomore at the university's department of chemical engineering.

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