Rex Tillerson is CEO of Exxon Mobil, an oil company that has repeatedly received negative ratings on the Human Rights Campaign's Corporate Equality Index.

Donald Trump may soon nominate Exxon Mobil's CEO, Rex Tillerson, as secretary of state.

NBC News first reported on the expected pick from anonymous sources — although a confirmation is still pending from the president-elect. Trump could make the announcement as early as this week.

The news has raised concerns among environmental activists, who worry about the head of an oil company — with business ties to Russian President Vladimir Putin — being America's top diplomat in an era when climate change has become a key issue on the international stage. Tillerson, 64, has no diplomatic experience, and has questioned scientific projections about the severity of global warming.

LGBT rights activists, pointing to Exxon Mobil's record regarding its policies toward LGBT employees, have also expressed concern. Chad Griffin, the president of the Human Rights Campaign, released a statement that urged top lawmakers to question Tillerson as to how he will address LGBT rights issues abroad.

"Exxon Mobil CEO Rex Tillerson's nomination raises critical questions as to how a Trump administration plans to protect LGBTQ employees and contractors affiliated with the State Department, and ultimately whether it will continue American efforts to advance equality through U.S. foreign policy,” Griffin stated.

“Will Trump and Tillerson take on brutal dictators like Putin who have inspired attacks against LGBTQ people? Will they assist LGBTQ Muslim refugees fleeing death from ISIS? For millions of people around the globe, their position on these and other issues are a matter of life and death. These are among the questions that Senators — Democrats and Republicans alike — must ask."

Exxon Mobil received a rating of 85 on this year's HRC's 2017 Corporate Equality Index, an annual tool that rates the policies and practices of U.S. employers regarding their LGBT employees. However, until recently, the rating was not this high.

Exxon Mobil was one of the last Fortune 500 companies to adopt written nondiscrimination policies prohibiting harassment and discrimination based on sexual orientation and gender identity. In 2012, and again in 2013, HRC gave Exxon Mobil a negative 25 out of 100 possible points. It is the lowest score ever received by any corporation. No other company has ever received a negative score. The Advocate devoted a full cover story in 2013 to the reasons why.

This article quoted one executive who served on the board of directors as saying that Exxon maintains a “‘kind of a 1950s Southern religious culture. They’re all engineers, mostly white males, mostly from the South…They shared a belief in the One Right Answer, that you would solve the equation and that would be the answer, and it didn’t need to be debated.’”

Activist Mark Reed-Walkup said a “culture of homophobia" made the company resistant to extending protections to LGBT employees at the time. The company's nondiscrimination policy did not include protections for LGBT workers until 2015, following President Obama's 2014 executive order that required federal contractors to do so.

Tillerson's views on LGBT rights are unclear. An Eagle Scout, he served as president of the Boy Scouts of America from 2010 to 2012. The youth organization had been criticized by LGBT activists for its longstanding bans on gay youth and leaders, which have since been lifted (in 2014 and 2015, respectively).

However, according to the Dallas Morning News, Tillerson was "instrumental" in helping end the ban on gay youth through lobbying the BSA's board, as attested by a colleague, John Hamre.

“I can’t get into the intimacy of these conversations. But he agonized over this. He prayed on it, and ultimately he came to the conclusion the only thing that can guide him here is what’s best for the young boys,” Hamre said. “I think he became a key leader in helping the group come to a consensus.”