Thirteen oil workers were reported dead and another 136 injured in the wake of Wednesday’s massive explosion at the Pajaritos Petrochemical Complex in the southern Gulf port of Coatzacoalcos. Tensions rose sharply Thursday, as hundreds of family members and coworkers of those still missing confronted heavily armed Mexican army troops backed by trucks mounted with machine guns deployed outside the facility’s entrance.

Pemex acknowledged that the death toll could still rise. The state-run oil company reported that 13 of the injured were in critical condition, some with severe burns to their respiratory systems from toxic gases, and put the number of missing at 18. The workers and their relatives, however, insist that this is a gross underestimation, with local media reporting as many as 80 missing workers.

The massive explosion was heard in towns as far as six miles away, and a towering plume of smoke rose over the plant, which manufactured vinyl chloride from highly flammable and toxic chemicals. The compound is used in the manufacture of PVC.

Survivors reported seeing workers’ shattered bodies thrown into the air by the force of the blast, walls toppled and windows blown out. Initially, residents of the surrounding area were told to stay inside their homes because of the danger posed by toxic gas. On Thursday, officials claimed that the danger had passed.

José Antonio González Anaya, the director general of Pemex, issued a statement promising a thorough investigation of the disaster and to determine culpability, “if there is any.”

Pemex is presenting all information in relation to the explosion, and, by the estimation of those seeking lost loved ones, doing it very slowly and badly. However, the plant itself was run by a private corporation, Mexichem, which gained control of the facility three years ago. This was on the eve of President Enrique Peña Nieto’s announcement of his so-called energy reform, hiving off Pemex enterprises to private capital. Mexichem, whose stock prices fell sharply Thursday, has remained largely silent on the tragedy.

“The magnitude of the explosion and the lack of communication with dozens of workers provoked among their families the sensation of being tricked, abandoned and frustrated, of being victims of an attempt to hide what had really happened,” commented local journalist José Luis Ortega Vidal.

Among the missing are employees of half-a-dozen different private contracting firms that were carrying out maintenance at the facility.

An employee of one of these firms, Alberto Díaz López, told the local newspaper NotiSur that a chlorine gas leak had been discovered, but that management had refused to evacuate workers from the area.

“We asked them if we could leave, but they told us that no, that this would be under control; when they said this they brought in electricians and welders, so that at the moment of the second explosion all of them were inside,” the worker said. He estimated the number of workers at the blast site at over 100.

There is a long history of fatal incidents at Pemex. The explosion is the worst disaster since 2013, when a gas explosion at the company’s headquarters in Mexico City left 32 dead. A year earlier, an explosion and fire at a Pemex gas facility in the northern state of Tamaulipas killed 30.

Just last February, a worker at the Pajaritos plant was killed, and in the same month two workers were killed and eight injured in an offshore oil platform fire in the Gulf of Mexico.

González Anaya, the Pemex director general, had just returned from a trip to the US for meetings with Wall Street financiers, rating agencies and oil company executives in a bid to privatize as much of the state-run oil company as possible, bidding it out to foreign investors and foreign energy conglomerates.

The company has been hard hit by the collapse in global oil prices. Production has fallen steadily for over a decade, declining from 3.4 million barrels in 2004 to 2.1 million barrels today. Earnings before taxes plummeted 124 percent last year, from 481 billion pesos in 2014 to negative 128 billion pesos in 2015.

The Pemex director made clear during his New York trip that the Mexican authorities are seeking private companies to take over majority interests in virtually every phase of oil production, including exploration, production, refining and transportation.

It has already reached a $2 billion deal with the private equity firms KKR, whose executives include former CIA director David Petraeus, and First Reserve Corp.

Asked how the disaster in Coatzacoalcos would affect these efforts to woo foreign investors, González Anaya dismissed the question: “It was an accident, and when there are human losses it makes it very regrettable, but I believe that one thing has nothing to do with the other.”

This is a lie. The privatization process and the destruction of Pemex jobs, working conditions and worker safety go hand-in-hand.

Pemex has carried out a series of sweeping cutbacks, putting over 10,000 jobs on the chopping block, attacking workers’ pensions and contracting out work in an attempt to cut losses and make the company more attractive to foreign investors. González Anaya is preparing another 100 billion pesos ($5.77 billion) worth of cost cutting for this year. The inevitable effect is the degeneration of facilities and increasingly unsafe conditions for Mexican workers.

Workers and family members gathered outside the gates of the devastated chemical plant Thursday turned their wrath against the van of an official in the National Oil Workers Union of the Mexican Republic (STPRM), breaking out its windows, flattening its tires and trying to turn the vehicle over. When another union van arrived on the scene, workers pelted it with rocks and chased it away.

The anger is well placed. The STPRM, a corporatist union apparatus tied closely to the government and the ruling Institutional Revolutionary Party (PRI), has been a full and well-paid partner in ripping up pension rights, jobs and conditions of Pemex workers.

The union’s corrupt president, Carlos Romero Deschamps, who is also a PRI senator, received some $21 million in payouts from the government in return for services rendered.

Part of those services is provided in the operations of the so-called Joint Commission on Safety and Health, which acts as a loyal servant of management, suppressing workers’ complaints and paving the way for each new accident and new death.

The criminal conditions confronting Pemex workers are reproduced on the other side of the US-Mexican border, with US oil workers suffering a total of 1,189 fatalities between 2003 and 2013. Thousands of oil refinery workers struck in February 2015 against health and safety conditions, including dangerous levels of mandatory overtime, and in defense of wages and benefits. That struggle was sabotaged and betrayed by the United Steelworkers union.