HONG KONG — Six months after a chemical spill killed tons of fish and devastated fishing communities along Vietnam’s central coast, anger over the episode is still raw, posing a challenge for a government that has struggled to address it.
In the latest sign of this festering outrage, thousands of demonstrators swarmed a steel factory in the central province of Ha Tinh on Sunday, echoing the street protests that erupted in the country’s major cities in April when photographs of piled-up fish corpses were widely shared on social media.
After weeks of silence, officials acknowledged in late June that the Formosa Ha Tinh Steel Corporation, the Taiwanese company that owns the steel factory, had caused the deaths by leaking chemicals into the adjacent South China Sea.
Formosa Steel admitted responsibility and agreed to pay $500 million in damages for what many Vietnamese consider one of the worst environmental disasters in the country’s modern history.
But residents of coastal villages and towns, where fishing drives the economies, have continued to hold boisterous rallies against the government and the company.
At Sunday’s rally, organized by a local Roman Catholic diocese, riot police officers outside the factory clashed with protesters before fleeing the scene,video and photographs circulating on social media show. Some of the protesters later climbed atop the factory’s outer wall.
Demonstrators said in telephone interviews on Monday that they had attended the rally to demand that Formosa Steel close the factory and compensate them for damages. Hundreds of people from Ha Tinh have sued the company in recent weeks, many with assistance from the Catholic Church.
“The government tried to hide information and protect Formosa,” said Tran Viet Hoa, a fisherman who said his income had fallen more than 70 percent because of the fish kill. “If Formosa remains in Vietnam and doesn’t give us our clean environment back, we will continue to protest.”
Another protester, Hoang Kim, said that he had seen more than 4,000 people at the rally and that many were Catholics. He said the protesters could have easily entered the factory compound but chose not to because they wanted only to make a point, not to vandalize property.
Online reports about the protest in the state-controlled news media were quickly removed by the Vietnamese authorities, activists said, but the rally was widely discussed on Facebook. Neither the Vietnamese Foreign Ministry nor senior Formosa Steel officials responded to requests for comment on Monday.
The fish kill, which has primarily affected Ha Tinh and three other central provinces, was not the first environmental problem to incite public outrage in Vietnam. Last year, hundreds of people staged weekly protests in Hanoi, the capital, over a government plan to chop down 6,700 trees from the city’s boulevards. The protests, coupled with indignation on social media, prompted city officials to postpone the plan indefinitely.
But the fish kill has had a broader national impact than the Hanoi tree protests, analysts say, in part because it has damaged the image of the seafood industry and caused many in the country to reconsider eating what is a staple of their diet.
In addition, many ordinary Vietnamese see Formosa’s Ha Tinh steel factory as a symbol of China’s economic influence in their country — a politically delicate topic that Vietnam’s one-party government has tried to play down, especially as China raises geopolitical tensions in Southeast Asia by aggressively pursuing its claims to disputed territory in the South China Sea.
There is no indication of any involvement by Beijing in the project, but some Vietnamese have focused on the presence of mainland Chinese workers there and have blurred the distinction between China and Taiwan, the self-governing island that Beijing claims as Chinese territory.
In May 2014, the factory was the site of violent protests over China’s placement of an oil rig in disputed waters in the South China Sea, off the Vietnamese coast. The factory was under construction at the time, and the construction workers were from a state-owned company from the mainland, the China Metallurgical Group, which had been hired to build it. During the same wave of violence, protesters also vandalized factories in southern Vietnam that were owned by companies from South Korea and Taiwan.
After four of the Chinese workers were killed, the Chinese government evacuated about 3,000 workers from the factory by ship.
This past June, after months of refusing to say definitively what had caused the fish kill, the Vietnamese government said it had occurred after Formosa Steel leaked phenol, cyanide and iron hydroxide into the sea from its steel plant.
But officials did not release any detailed scientific evidence to support their conclusion, raising questions about whether other contaminants had been detected but not publicly reported, said Nguyen Duc Hiep, an environmental scientist in Australia and a visiting researcher at Ton Duc Thang University in Ho Chi Minh City, Vietnam.
“If there are heavy metals — for example, lead, mercury, cadmium, arsenic — then it will stay in the environment for a very long time, and it’s very toxic because it can go up the food chain and cause a lot of damage,” Professor Hiep said, adding that the three chemicals that were publicly disclosed were not necessarily toxic to fish in the long term.
“A lot of people suspect the reason the scientific report didn’t come out is because there were a lot of heavy metals,” he added.
The state news media has reported that the fish kill resulted in tens of thousands of lost jobs in the affected provinces, and protesters are questioning the government’s suggestions that the problem has largely been resolved.
Nguyen Viet Thanh, a professor of environmental economics at Vietnam National University in Hanoi, said it was difficult to separate the effects of the toxic spill from the impact of overfishing and other problems that have long affected Vietnam’s coastal waters.
But he said a general lack of trust in the government, along with the factory’s associations with mainland China and Taiwan, had damaged consumer confidence in the domestic seafood industry and made it difficult for many fishermen on the central coast to make a living.
Conflicting accounts about the fish kill by several ministries in the weeks after the event only added to the suspicions, said Le Quang Binh, former director of the Hanoi-based Institute for Studies of Society, Economics and Environment. And because so many Vietnamese were debating the issue on social media, he added, they were able to spot inconsistencies and demand more public accountability. “In Vietnam, traditionally people avoid politics because it’s sensitive,” Mr. Binh said. “But now, more people understand that they cannot avoid politics because politics and policy can affect their lives.”
One sign of public engagement with the controversy is the hashtag#IChooseFish that is popular on social media — a mass response to a Formosa Steel spokesman saying at an April news briefing that the Vietnamese should decide whether to catch fish or “build a modern steel industry.” A cartoon that circulated on Facebook in the spring imagined President Obama, who visited Vietnam in May, uttering the phrase “I choose fish” at a dinner with Vietnamese officials.
Jonathan D. London, a Vietnam expert at Leiden University in the Netherlands, said the intense public interest in the fish kill presented an acute problem for Vietnam’s top leaders, who took office in the spring.
“They’re trying to do something that no leaders have had to do in the past,” he said, “which is essentially address public outrage that is being freely expressed on a daily basis.”