From designer baby clothes and classic cars to antique furniture and name-brand electronics, you can find treasures and bargains galore on Facebook Marketplace, the online bazaar where Facebook users sell new and used goods to buyers in their local area. Unfortunately, the classified listings on Facebook Marketplace don’t just include the practical, like new pots and pans, or the quirky, like a rare bobblehead of musician Jimi Hendrix. Sometimes, they also include the alarming—like environmental crimes.

The plots, some of which are as large as 1,000 soccer fields, often belong to national forests or to indigenous tribes. Nevertheless, landgrabbers illegally claim them as their own, then try to sell them to farmers and cattle ranchers. Sometimes, they deforest the land before they list it because selling it as “farm-ready” makes it more valuable to agricultural interests.

The most nefarious landgrabbers seize protected land, then deforest it in order to deliberately ruin it. Once it’s stripped of its natural resources, the BBC says, they lobby politicians to abolish its protected status on grounds that there’s nothing left to conserve. If they succeed, they can then purchase the land from the government and thereby legitimize their ownership claim.

Environmentalists say the Brazilian government is looking the other way. “The situation is really desperate,” conservationist Raphael Bevilaquia, a prosecutor in the Brazilian state of Rondônia, told the BBC. “The executive power is playing against us. It’s disheartening.”

“We are updating our commerce policies to explicitly prohibit the buying or selling of land of any type in ecological conservation areas on our commerce products across Facebook, Instagram, and WhatsApp,” the social media giant explained in an Oct. 8, 2021 blog post, in which it said it will now review Facebook Marketplace listings against an international database of protected land to identify listings that may violate its new policy. “Protected areas are crucial for conserving habitats and ecosystems and are critical to tackling the global nature crisis. Based on specific criteria, Facebook will seek to identify and block new listings in such areas. By using complementary information sources like this database, we are adding another barrier for people trying to list these lands on Marketplace.”

It took Facebook nearly eight months to change its tune: In its initial reaction to the BBC’s reporting, it said it would “work with local authorities,” but declined to take action of its own.

Still, conservationists say Facebook’s action is better late than never. “I think this announcement is a good thing. Although it’s coming late, because they should never have allowed those ads,” Ivaneide Bandeira, head of Brazilian environmental defense organization Kanindé, told the BBC. “But the fact that they are now taking this position is good because it will help to protect the territory.”

Not everyone is so sure that it will be helpful. “If they don’t make it mandatory for sellers to provide the location of the area on sale, any attempt at blocking them will be flawed,” Brazilian lawyer and scientist Brenda Brito told the BBC. “They may have the best database in the world, but if they don’t have some geo-location reference, it won’t work.”

Facebook—whose actions coincided with a global outage of its websites, as well as scathing critiques from whistleblower Frances Haugen—conceded that its efforts are only the beginning of what could be done. “We know there are no ‘silver bullets’ in this topic and we will continue to work to prevent people from circumventing our inspection,” a company spokesperson told the BBC.