The agency also said the arrival of the toxic cargo had violated the Basel Convention on the movement of hazardous waste, of which both the UK and Brazil are signatories, which came into force in 1992.
Ingrid Oberg, regional chief of Ibama, later told the BBC the cargo mainly consisted of domestic waste.
"It's a lot of food containers and cleaning product containers. We found old clothes, shoes, papers, a lot of old newspapers.
"In some of the containers recently found there were also some technological products, like DVDs, pieces of computers, plastic stuff. But mainly it's domestic garbage."