Blackstone has denied the claims at the center of Warren’s letter, which was also signed by a handful of top Democrats. The company in September pushed back on an August story by the Intercept linking Hidrovias to deforestation by its development of a controversial highway, known as BR-163, through the jungle. Blackstone says the road has been operated by the Brazilian government since 1976.

“This is a total fabrication," Blackstone spokesperson Matthew Anderson said in a statement Monday. "Hidrovias didn’t build, own, or operate the road in question, and the company doesn’t transport products produced in the Amazon biome. In fact, by shifting traffic from trucks to barges, the company significantly reduces greenhouse gases.”

The Democrats conceded that the “road remains publicly owned” but said “Hidrovias has consulted with and helped finance the Brazilian government’s efforts to develop and find funding mechanisms to pave BR-163, maintain the road, and reduce congestion to accelerate its shipments.”

The road, a soybean shipping route, “ultimately causes deforestation directly and indirectly accelerates the transition of the Amazon rainforest from jungle to farmland by incentivizing further agriculture development,” the lawmakers wrote.

“By financing the company that profits from this destruction, Blackstone’s investments appear to pave the way for further deforestation and an exacerbated climate crisis,” they added.

The lawmakers asked Blackstone to provide disclosures on the firm’s investments and their environmental impacts by Jan. 10.

This isn’t Warren’s first jab at private equity firms, which she has likened to “vampires” over their use of leveraged buyouts. She introduced legislation in July that would hold private equity firms liable for problems at companies they take over.