Local residents gather in front of a municipal government building in Shifang county, Sichuan province, in this handout picture taken Monday.
Updated at 10:52 a.m. ET: While Shifang city government officials have announced that construction on the refinery will be halted, some residents have continued to protest in the streets to demand the release of some protesters detained during the protests including an unknown number of college students from a nearby aviation academy.
BEIJING -- Construction of a copper factory in central China has been halted, an official said Tuesday, after days of angry protests over fears of pollution culminated in clashes that saw riot police fire stun grenades and tear gas to break up a crowd of thousands.
Residents of the town of Shifang, Sichuan province, have been slowly gathering around a local city government office since Saturday, the day after a foundation-laying ceremony put on by Sichuan Hongda – a conglomerate specializing in minerals, real estate and finance – to celebrate the first phase of construction on the $1.64 billion proposed molybdenum-copper alloy refinery nearby.
When -- or now if -- completed, the refinery could generate an estimated $8 billion a year.
According to local Sichuan newspaper reports, the protest started with around a dozen people, but by Sunday it had grown as fellow residents and high school students joined them.
By Monday, there was a crowd of thousands, a police officer on duty there told the Chinese newspaper, Global Times. However, the South China Morning Post reported the figure was in the tens of thousands.
By early Monday afternoon, tensions had escalated and protesters attempted to occupy the city government offices, forcing their way past police inside where they reportedly threw bricks through windows and destroyed offices there. Riot police were brought in to restore order, firing tear gas and stun grenades to break up the crowd.
Some 13 injuries were initially reported by official state media, but witnesses on the ground reported far more wounded.
As of late Tuesday afternoon, protesters were reportedly still on the streets of Shifang, effectively locked in a standoff.
Local government officials were facing pressure from provincial-level and central government leaders to stifle social unrest.
'No longer suitable for living'
A protester surnamed Wang told NBC News that their numbers had thinned out as the city boosted its police presence.
“The two sides are just standing, facing each other,” Wang said. “There are a lot of police and the roads are blocked.”
“Yesterday, the protesters were all concentrated in front of the government building,” said another protester who requested anonymity. “But today, the police have blocked all the roads around the government building so people cannot concentrate in one area and are scattered everywhere… I am not sure how many people there are, but fewer than yesterday."
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Asked what he would do if construction went ahead on the refinery, the man responded, “As far as I’m concerned, I have settled here, but this place will be no longer suitable for living.”
“If my economic situation and other conditions meet, I will definitely move away," he added.
Concerns over the pollution created by the alloy refineries that dot China’s resource-rich regions have grown in recent years as China’s economy develops and its people become better educated about the effects of industrial waste on human health.
“I think in general smelters are heavily polluting facilities no matter what, they smelt,” said Ma Tianjie, a Greenpeace campaigner in China specializing in heavy metal waste. “We have seen a lot of cases with heavy metal smelters where there is substantial release of all kinds of toxic pollutants.”
Those pollutants are released into the air through smoke and into the nearby area's ground and water supplies through the highly toxic slag waste that is a byproduct of a refinery’s production phase. Arsenic, an element that can cause severe kidney and liver problems in humans, is often found in worrying levels in this slag.
As these health concerns have become increasingly more public, so too has opposition to these refineries in urban areas.
While companies and local governments have up until now been largely able to duck growing NIMBY-ism in urban centers around China, officials here are increasingly finding themselves accountable for the environmental legacy of these lucrative, but highly polluting industries.
A legacy that Ma warns can stay with a population for a long time. “Generally the smelters will leave a quite heavy legacy to the local community” he warned, “even decades after the facilities leave.”
The mass public protest in Shifang has for now, had its desired effect: Late Tuesday afternoon, Shifang’s local Communist Party chief, Li Chengjin, announced through the government’s Weibo microblog feed that the government was halting construction of the refinery and would no longer allow it to go ahead.
“It’s definitely a piece of good news that construction is being halted, this is absolutely what we wanted,” said Wang upon hearing the news of the government’s decision to halt construction.
However, similar recent cases suggest that such success could just be temporary. Last summer, thousands of residents of the northeastern port city of Dalian took to the streets to protest a chemical factory after a dike broke following a storm, potentially exposing the city to the threat of a toxic spill.
Local officials were successful in keeping the crowd peaceful and eventually broke up the protests when they emphatically pledged to halt production at the factory and have it moved out of the city.
But production resumed soon after, though local officials there have stressed since then that the factory was still slated to be moved.
NBC News’ Horace Lu contributed to this report.
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