Dams Cajati, state of São Paulo Dams Cajati, state of São Paulo Dams Dam Dam Cajati, state of São Paulo 11,000 people estimated in high-risk areas. Map) Owner: Mosaic Fertilizantes P&K The New York Times/Satellite photograph by Google.

Brazil counts 87 mining dams built using the same method, known as upstream tailings construction, as the one that collapsed. That design is risky if not monitored carefully, and experts have warned that a collapse could happen again in a country where neither the mining industry nor regulators have the situation under control.

We looked at each of the 87 upstream dams to estimate if it could threaten populated areas, using geospatial analysis to estimate where the mud could flow if each of the dams failed. For at least 27 of those dams, more than 1,000 people live in high-risk areas. That means they are downhill from the dam and within eight kilometers — the distance the mud flowed after the Brumadinho collapse.

All of those dams were rated by the government at the same risk level, or worse, as the dam that failed in Brumadinho.

“I wouldn’t buy a home downstream of a tailings dam built in an upstream fashion,” said William F. Marcuson III, a former president of the American Society of Civil Engineers. “And I wouldn’t allow my mother to rent or live in a home downstream of a tailings dam built in an upstream fashion.”

Here’s a look at where people may be at risk and which companies own the dams, as well as rough estimates of how many people live in high-risk areas:

Most of the dams are located in the state of Minas Gerais

Two dams Brumadinho, Casa Branca neighborhood Two dams Brumadinho, Casa Branca neighborhood 2,000 people estimated in high–risk areas. Owner: Mineração Geral do Brasil (Map) Dam Congonhas Congonhas 5,500 people estimated in high–risk areas. Owner: CSN Mineração (Map) Dam Conselheiro Lafaiete Conselheiro Lafaiete 5,000 people estimated in high–risk areas. Owner: Companhia Siderúrgica Nacional (Map) Igarapé Two dams Igarapé 14,000 people estimated in high–risk areas. Owner: Mineração Morro do Ipê (Map) Itabirito Four dams Itabirito 1,500 people estimated in high–risk areas. Owner: SAFM Mineração; Minar Mineração Aredes (bottom dam). (Map) Dam Dam Itatiaiuçu Itatiaiuçu 3,000 people estimated in high–risk areas. Owner: Mineração Usiminas (Map) Dam Nova Lima, Jardim Canadá neighborhood Nova Lima, Jardim Canadá neighborhood 3,000 people estimated in high–risk areas. Owner: Minerações Brasileiras Reunidas (Map) Dam João Monlevade João Monlevade 1,500 people estimated in high–risk areas. Owner: ArcelorMittal (Map) Dam Nova Lima Nova Lima 5,500 people estimated in high–risk areas. Owner: Vale (Map) Two dams Pires neighborhood, Congonhas Pires neighborhood, Congonhas 7,500 people estimated in high–risk areas. Owner: Nacional Minérios (Map) The New York Times | Satellite images by Google.

Minas Gerais, a state whose name means “general mines,” has been the hub of Brazil’s mining industry for centuries. Today, it still produces 53 percent of the country’s mining output.

Belo Horizonte João Molevade Esmeraldas Contagem Betim Nova Lima Brumadinho Site of dam collapse Ouro Preto MINAS GERAIS Conselheiro Lafaiete Upstream mining dams near populated areas BRAZIL Upstream mining dams 10 miles Belo Horizonte João Molevade Contagem Betim Nova Lima Brumadinho Site of dam collapse Ouro Preto MINAS GERAIS BRAZIL Upstream mining dams near populated areas 10 miles Upstream mining dams MINAS GERAIS Belo Horizonte João Molevade Contagem Betim Nova Lima Brumadinho Site of dam collapse Ouro Preto BRAZIL Conselheiro Lafaiete Upstream mining dams near populated areas Upstream mining dams 10 miles The New York Times

Dams in Other States