The cause of last week’s death of a carriage horse in Central Park has been blamed on a poisonous plant, according to a new report.

The Transport Workers Union of America, the union representing carriage horse workers, released details Tuesday morning from a reported necropsy done by Cornell University’s College of Veterinary Medicine. According to that report, Deniz died on June 10 after ingesting a “lethal” amount of Japanese yew.

The 16-year-old horse collapsed on West End Drive around 8 p.m., catching the attention of parkgoers and concerned onlookers who rushed to try and save the horse.

“Deniz’s tragic death was not caused by neglect or abuse or the fact he was a carriage horse – as some animal rights activists and elected officials claimed,” TWU Administrative Vice President Alexander Kemp said in a statement sharing details of the necropsy.

Kemp pointed blame at the Central Park Conservancy, which he claimed “never warned anyone that there were deadly yew plants in the park.”

The conservancy quickly disputed the union’s claims.

“TWU has now demonstrated how their own negligence has resulted in this unfortunate incident, since NYC Parks rules plainly forbid horses from eating vegetation anywhere across our 843 acres,” the conservancy said in a statement.

“The same rule requires carriage drivers and operators to attend to their horses at all times in order to keep them safe and healthy. Perhaps if they had, Deniz would not have suffered as he did, and died.”

Deniz’s tragic death spurned a fresh round of outcry over the use of carriage horses and concerns about the health and wellbeing of the animals.

The carriage driver told NBC New York last week that the horse was perfectly healthy, eating and drinking throughout the day, and then fell to the ground.

“He just go try to pee and in two seconds he’s dying,” the emotional driver said. “I lost someone from my family — but they treating me like a horse abuser, which is not true. The horse was totally healthy.”

NYCLASS said they have been working with members of City Council to reintroduce a bill that would ban horse carriage rides in Central Park, and were more hopeful it could pass with the new administration in charge.