Taiwanese-owned Formosa Plastics is building Southeast Asia’s largest steel mill in central Vietnam.

Since April 4, when the plant is suspected to have released a torrent of toxic chemicals into the sea, more than 70 tons of dead fish have washed up on Vietnam’s shores.

Aggressive efforts to spin the news have made little headway against a rising tide of criticism on Facebook and online political blogs.

Vietnam has bet its future on its ability to attract — and learn from — foreign investors. It has a young workforce, low wage rates and a streamlined approval process for investment. Foreign capital has surged into VN in the last few years, much of it bearing the prestigious marques of multinational corporations.

Now a devastating fish kill along the nation’s central coast has Vietnam’s government tied up in knots and its citizens muttering that the regime has been far too ready to drop environmental protection standards.

Circumstantial evidence points to a massive release of toxic chemicals at Vung Ang, a bay on Vietnam’s north central coast, on April 4. Prevailing currents carried the poisons south-southeast along the heavily indented coastline for approximately 200 kilometers.

When Vietnam’s national media picked up the story circa April 24, units of Vietnam’s Fisheries Agency had already counted some 70 tons of dead fish washed up on the beaches of four provinces. Subsequently there were also reports of the collateral decimation of fish-eating seabird colonies.

The blow to the economy of the four provinces has been considerable: in particular, thousands of fishermen idled, the markets emptied of seafood, and a sharp fall-off in tourist visitors.

Vung Ang is the site of a huge foreign-invested project that’s just coming online. Already over $10 billion has been spent to develop the Formosa Ha Tinh Steel Company (FHS) complex, a deepwater port and ancillary facilities. When complete, it will be the biggest steel mill in Southeast Asia,

Ha Tinh province officials campaigned for years to land the FHS project. They have reportedly viewed it as the key to turning around the fortunes of their backwater province. They, and top officials of the central government as well, seem markedly reluctant to tie FHS to the extraordinary fish kill.

A few days after the disaster focused national attention, the Ministry of Natural Resources and Environment proposed that it was the result of a red tide, or of toxic chemical contamination traceable to human activity, or maybe of both. Organs of the ruling Communist Party were quick to run with the red tide theory, and just as quickly derided when pinkish illustrations posted on their websites were revealed to have been photoshopped.

Aggressive efforts to spin the news are a reliable indicator of disarray within Vietnam’s single-party regime. They began in earnest on the eve of the May Day holiday weekend, but made little headway against a rising tide of criticism on Facebook and online political blogs. These social media are tremendously popular in Vietnam and, because they are beyond the reach of the internal security services, they are where citizens find and debate the daily news that the state-supervised media may not print.

The tone of online comment shifted over Vietnam’s three-day weekend from urging the government to focus on what connection FHS may have had, or not had, with the great fish kill, to accusations that the authorities were deliberately shielding the Taiwanese-owned company.

Hunkered down in its 3,300-hectare project site, FHS management had stated flatly on April 26 that all of its activities complied with Vietnamese laws and regulations and that it knew nothing that would explain the shoals of dead fish that had washed up from Vung Ang south. It added that it had spent $45 million on a state-of-the-art waste management system, including a 1.2-meter pipe that runs under the seabed to a point 1.3 kilometers offshore where waste that had been rendered harmless to the environment is released.

Absent any other plausible explanation of what might have killed the fish, Vietnam’s internet-enabled public has seized on reports that FHS had imported a large quantity of chemicals to purge the newly installed waste management system and that Vietnamese divers working for a project contractor had observed a huge discharge of reddish liquids from the mouth of the pipe on April 4.

As information seeps into the national online dialogue about the dodgy environmental record of the parent company, Formosa Plastics, the Vietnamese public’s view of FHS is hardening. Formosa Plastics is the world’s #2 producer of polyvinyl chloride, a material with many uses, from plumbing pipes to bank cards. Over the past 20 years, the company has been extensively litigated against for environmental lapses in Taiwan, Cambodia and the U.S.

The general contractor for the FHS plant is the Chinese state-owned firm MMC, or China Metallurgical Group. That’s another red flag for Vietnamese public opinion which, not without reason, regards a “rising China” as intent on economic and political domination of its one-time vassal state.

A bit of sympathy must be reserved for Vietnam’s leaders, the winners of an intraparty struggle in January, who are grappling with their first political crisis. It’s exceedingly difficult to assemble prosecutable evidence in cases like this one, however plausibly causation may be reasoned by eliminating all the alternatives. That’s not good enough to satisfy aroused citizens. To quote a representative blogger, “the slow response of the government and silence of party leaders indicates there are some political ‘forces’ preventing quick actions.”

That may well be the case. Political corruption is endemic in Vietnam and though the new #1, Communist Party leader Nguyen Phu Trong, says he’s determined to clean it up, the culture of opacity the party fosters feeds suspicion that FHS has paid off a goodly number of officials, high and low.

In any event, vis-a-vis the Great Fish Kill, the government hasn’t got a smoking gun and unless one comes to hand, it has scant leverage on FHS.

Questioned by reporters on April 25, Chow Chun Fan, the FHS liaison officer in Hanoi, dropped a clanger. Vietnam must choose, he said: “Do you choose fish or do you choose steel?” Immediately and predictably, Chow was roasted by Vietnamese media and disowned by his superiors at FHS headquarters.

Reflecting on Chow’s arrogant statement, however, some Vietnamese commentators have acknowledged its essential truth. Vietnam ought to be less eager for foreign investment at any price, they argue, and more aware that environmental costs are inherent in industrial production. For a nation as eager to become wealthy as Vietnam, their conclusion is unimpeachable: the nation cannot close the doors to foreign investment, but it must be very clear on the trade-offs in any deal. Once clear, it must choose projects that maximize the opportunities for economic growth and minimize the risks to the environment and to public welfare.

By that standard, giving FHS the green light may have been the wrong choice.

David Brown, a retired American diplomat, is now a frequent writer on contemporary Vietnam. His e-mail address is [email protected]

*An earlier version of this article mistakenly referred to the FHS complex as including the largest steel mill in Asia.