On the outskirts of Mexicali, where cattle graze and tractors roll across the farmland, a sooty building belches out clouds of smoke.
Twisted scraps of metal and the smashed skeletons of old cars sit in piles next to the hulking plant, where machinery hums loudly, punctuated by the booming sounds of metal striking metal.
Outside the plant’s walls and across a narrow dirt road, Blanca Ramírez lives in the same farmhouse where she grew up. She remembers when she was a kid, before the steel mill was built, the land across the road was an alfalfa field and the air was clean.
Now smoke pours out of the plant at all hours, floating over a row of houses and across the fields.
“The pollution has gradually increased, because we didn’t used to see as much as we see now,” Ramírez said, standing on the road beside the plant. “It’s terrible.”
The Grupo Simec steel mill is a huge recycling facility. It devours metal scraps and the chassis of old cars, which arrive on trucks from junkyards where they have been stripped of parts. The metal goes in dirty, covered with paint and rust, and is melted down along with iron ore and carbon coke, then emerges clean as pieces of steel rebar for construction, stacked in bundles on trailers.
The smelting process separates impurities from the molten iron and leaves behind waste: heaps of grayish black slag, which in other places has been found to contain calcium, silicon, iron, chromium, manganese, lead and other metals and pollutants.
Some of the slag is piled inside the compound’s walls, looking like rolling hills.