Just after nine o’clock on a Tuesday morning in June, an environmental activist named Bill Kayong was shot and killed while sitting in his pickup truck, waiting for a traffic light to change in the Malaysian city of Miri, on the island of Borneo. Kayong had been working with a group of villagers who were trying to reclaim land that the local government had transferred to a Malaysian palm-oil company. A few days after the murder, the police identified Stephen Lee Chee Kiang, a director and major shareholder of the company, Tung Huat Niah Plantation, as a suspect in the crime, but Kiang flew to Australia before he could be questioned by authorities. (Three other individuals were eventually charged in the case.) Around the world, environmental and human-rights activists added Kayong’s death to the tally of violent incidents connected to the production of palm oil, which has quietly become one of the most indispensable substances on Earth.

The World Wildlife Fund says that half of the items currently on American grocery-store shelves contain some form of palm oil. (“You’re soaking in it,” went the old tagline of the palm-oil-based dish detergent Palmolive.) The move away from trans fats in processed foods was a particular boon for the industry—semi-solid at room temperature, palm oil emerged as an ideal swap-in for the partially hydrogenated oils formerly used to enhance the texture, flavor, and shelf life of products like cookies and crackers. Since 2002, when a report from the National Academy of Sciences found a link between trans fats and heart disease, palm-oil imports to the U.S. have risen four hundred and forty-six per cent, and have topped a million metric tons in recent years. In addition to its widespread use in processed foods, the oil palm plant, Elaeis guineensis, lurks in one form or another in many cosmetics and personal-care products, such as shampoos, soaps, and lipsticks. It’s also used in animal feeds and industrial materials, and, increasingly, as a biofuel.

Elaeis guineensis is native to West Africa, and while its cultivation has spread recently in Central and South America and across equatorial Africa, eighty-five per cent of the palm oil produced today comes from Indonesia or Malaysia. Rising palm-oil exports have helped both countries make enormous economic strides in the past few decades, but the growth has come at a cost: deforestation rates in both places have been listed among the highest in the world. The habitat destruction brought about by palm-oil production has helped push scores of the region’s species, including orangutans and Sumatran elephants, rhinos, and tigers, to the brink of extinction. And, mostly thanks to palm-oil production, Indonesia can boast some of the world’s highest levels of greenhouse-gas emissions.

Yet it is violence—against local populations, farmers, and activists—that has human-rights groups closely watching the palm-oil industry. The reports are often sad echoes of one another. In 2012, a human-rights lawyer named Antonio Trejo Cabrera was ambushed by gunmen while walking out of a church in Tegucigalpa, Honduras. Trejo had been representing local peasant organizations in a fight against the palm-oil company Grupo Dinant, and had recently won a handful of cases forcing the company’s plantations to be turned over to local residents. “I probably had reasons to kill him, but I’m not a killer,” Miguel Facussé, then the owner of Grupo Dinant, told a reporter for the Los Angeles Times, later that year. The company was never linked to Trejo’s murder. But in 2013 the International Finance Corporation, an organization affiliated with the World Bank, investigated Grupo Dinant and, citing allegations that forty different murders could be linked to its plantations, security guards, and third-party security contractors, declined to provide the company with a multimillion-dollar loan installment. Most of the victims in the cases cited by the I.F.C. were local farmers and activists. (“While we vehemently deny the ridiculous claims made against us nor do we claim to be perfect,” Roger Pineda, a Grupo Dinant spokesman, wrote to me in an e-mail, in response to my questions about Trejo and the allegations made by the I.F.C. “We have made great efforts over the last two or three years to acknowledge, assume responsibility for, and correct our mistakes—professionally and openly—and learn from them.”)

In September of last year, a twenty-eight-year-old Guatemalan schoolteacher named Rigoberto Lima Choc was killed on the steps of a courthouse in the city of Sayaxché. Choc had led a group of activists that had filed a criminal complaint against the palm-oil company Reforestadora de Palmas del Petén, S.A., known as REPSA, based on evidence that REPSA’s overflowing effluent ponds had triggered a large fish kill along a sixty-five-mile stretch of the Pasión River. Choc was shot the day after the judge overseeing the case ordered the six-month closure of REPSA. The company, at the time, issued a statement rejecting “any link of the company with the murder.” Then, in June, it instituted a new anti-violence and intimidation policy, which pledges to “promote safe and secure communities in which we operate.”

In a recent report, the London-based organization Global Witness highlighted the ways that environmental activism is being increasingly criminalized in Central and West Africa, where the palm-oil industry has invested billions of dollars in recent years. In Cameroon, for example, the director of a group that has opposed the development of a major palm-oil plantation was convicted last year of defamation, propagation of false news, and unlawful assembly in connection to his work; in Sierra Leone, community activists who have denounced palm-oil operations have faced repeated harassment, arrests, and detention; and, in Liberia, a protest in May, 2015, near a palm-oil plantation was broken up by police armed with assault rifles.

In theory, at least, the palm-oil industry has committed resources to monitoring itself and preventing abuses: a number of multinational companies and N.G.O.s working in the sector came together in 2004 to establish the Roundtable on Sustainable Palm Oil (R.S.P.O.). But the organization’s record has been spotty, at best, and even a R.S.P.O. representative acknowledged to me that the process it uses to certify palm-oil producers is “not perfect.” (Just last month, a prominent R.S.P.O. member, Wilmar International, was criticized publicly by Amnesty International for its use of child and forced labor; the company responded with a statement acknowledging the allegations, but pointed to the problems plaguing the whole industry: “The focus on Wilmar . . . is often used to draw attention to problems in the wider palm oil industry.”)

“You’re working in areas where there’s no infrastructure, there’s no governance, there’s bribery,” Stefano Savi, who oversees global outreach for R.S.P.O., told me a few months ago. “We shouldn’t be naïve in thinking that these issues can be solved from the night to the day.”

In any case, only a fraction of global palm-oil production is currently certified by R.S.P.O. Given the enormous size of the industry, and the length of the supply chains involved, tracking all the environmental and human-rights issues related to palm oil worldwide is a practical impossibility. “There’s an awful lot at stake,” Nigel Sizer, the president of the New York City-based Rainforest Alliance, which works with palm-oil producers in Indonesia, Latin America, and Papua New Guinea, told me. “Massive investments in plantations. The infrastructure involved in processing. You get in the way of that, and you’re going to be dealt with in the most brutal way imaginable.”

I recently spoke by phone with Baru Bian, a Malaysian politician who was a friend of Bill Kayong, the activist killed in June. Just a few weeks ago, Bian told me, yet another man was killed during a protest at an oil-palm plantation in the town of Mukah. Meanwhile, Kayong’s family is still waiting to see if any of the individuals charged in Kayong’s murder will be convicted. “They are left without their husband and father,” Bian told me. “Still waiting for justice to be done.”

This story was produced with support from the Food & Environment Reporting Network (FERN), a nonprofit investigative journalism organization.