Jeff Zelevansky / Reuters David Buckel led a lawsuit involving the 1993 murder and rape of a transgender man. The case was later adapted into the film "Boys Don't Cry."

David Buckel, a prominent LGBTQ civil rights attorney, fatally set himself on fire at Prospect Park in Brooklyn, New York, early Saturday morning.

He was 60 years old.

In a suicide note left near his body, Buckel said he had used “fossil fuel” to ignite the fire and wanted his death to symbolize what humans are doing to Earth, the New York Daily News reported. Buckel emailed copies of the note to several news organizations, including the New York Times.

“Pollution ravages our planet, oozing inhabitability via air, soil, water and weather,” Buckel wrote in his note, according to the Times’ copy of the note. “Most humans on the planet now breathe air made unhealthy by fossil fuels, and many die early deaths as a result — my early death by fossil fuel reflects what we are doing to ourselves.”

Buckel worked with several environmental groups, including doing volunteer work with the Added Value Red Hook Community Farm and acting as the senior organics recovery coordinator for the Brooklyn Botanic Garden’s NYC Compost Project.

But his more prominent achievements came in his work as a civil rights lawyer.

Buckel was a senior counsel and director of the Marriage Project for Lambda Legal, an LGBTQ advocacy group. He argued in many landmark cases involving LGBTQ youth, including a lawsuit against the Boy Scouts of America and its former ban on gay members.

Camilla Taylor, director of Lambda Legal, said in a statement to HuffPost that their organization will honor Buckel’s life by “continuing to fight for equality.”

“The news of David’s death is heartbreaking,” Taylor said.

“David was a brilliant legal visionary. David helped create Lambda Legal’s focus on LGBT youth,” Taylor continued, detailing Buckel’s work on a case that led a federal court to rule that schools “have an obligation to prevent anti-gay bullying.”

She added: “His thoughtful and engaging advocacy broke through many stubborn misconceptions and showed it was possible and necessary for our movement to speak up for bullied, ostracized LGBT young people.”