A major oil spill earlier this month in the Ecuadorian Amazon has sparked criticism of cleanup efforts and the lack of transparency from the government regarding the spill’s environmental impact.

An oil pipeline operated by the state-owned Petroecuador ruptured earlier this month outside of the city of Nueva Loja, the capital of the province of Sucumbíos, causing concern about contamination of the region’s watershed.

A company statement said the rupture occurred after someone attacked the pipeline — known officially as the Trans-Ecuadorian Pipeline System (SOTE) — and that it was intentionally executed at a spot that would leak into the river. However, the company didn’t say who was responsible or how the attack was carried out.

The SOTE, considered by the government to be “one of the most important pieces of infrastructure in the country,” is approximately 500 kilometers (310 miles) long, transporting around 360,000 barrels of oil out of the Amazon every day, or around 70% of the country’s total production.

Despite being one of Ecuador’s most important industries, oil is also one of the most environmentally harmful. There have been over a thousand reported oil spills in the Ecuadorian Amazon over the last decade.

Environmental activists questioned claims that the spill was the result of an attack, saying most of the pipeline is underground and would require special machinery and expertise to access.

“If we’re talking about sabotage, the government would have to show the evidence it has and what the purpose of the sabotage was,” said Jorge Acero, the legal defender’s program coordinator for Amazon Frontlines, an environmental organization.

Amazon Frontlines criticized Petroecuador for a lack of transparency regarding the incident, pointing out that it’s required to share basic data about the spill within 24 hours, including the number of barrels lost and the geographical reach. It’s also supposed to share what measures it’s taking to clean up the oil and stop it from spreading.

“There’s no transparency regarding the measures adopted,” Acero said.

The company reportedly installed barriers meant to stop the oil from traveling down the Conejo River, which flows into the San Miguel River near the border with Colombia. Other photos of workers cleaning up the rivers were published on social media.

“The public company rejects these criminal acts that threaten this infrastructure that transports the crude oil of all Ecuadorians,” it said in a statement. “It also reports that thanks to the timely action of the EP Petroecuador teams, the emergency has been controlled.”

However, some communities have reported visible oil contamination in the water, which is commonly used for bathing, washing, and drinking. The long-term effects on fish and vegetation, as well as oils that mix into the sands of the riverbed, will hurt the entire ecosystem, critics warned.