Agent Orange is a forest-clearing herbicide that killed over 400,000 people during the Vietnam War. Almost 40 years later, ranchers in the Amazon region of Brazil are still using the substance to illegally clear out 440 acres of rainforest.

According to Treehugger and the Brazilian environmental agency IBAMA, ranchers have turned to Agent Orange as a deforesting method because it's difficult to detect.

Officials from Brazil's environmental agency IBAMA were first tipped to the illegal clearing by satellite images of the forest in Amazonia; a helicopter flyover in the region later revealed thousands of trees left ash-colored and defoliated by toxic chemicals. IBAMA says that Agent Orange was likely dispersed by aircraft by a yet unidentified rancher to clear the land for pasture because it is more difficult to detect than traditional operations that require chainsaws and tractors.

In addition, four tons of (fortunately) unreleased Agent Orange was discovered in another part of the Amazon, which would have wiped out 7,500 acres of foliage and wildlife, and would have caused catastrophic consequences for decades to follow. According to Brazilian publication Folha de Sao Paulo, this is the first time since 1999 that Agent Orange has been used in Brazil. [IBAMA and <a href="http://www.treehugger.com/files/2011/07/...">Folha de Sao Paulo via Treehugger]