LA OROYA, Peru  Claudia Albino, a washerwoman who earns about $3 a day and lives in a one-room hovel with her family in this bleak town high in the Andes, might seem at first to have nothing to do with Ira Rennert, the reclusive New York billionaire who built one of the largest homes in the United States, an Italianate mansion sprawling over more than 66,000 square feet in the Hamptons.

But Mr. Rennert’s privately held industrial empire includes the smelter with a towering smokestack that overlooks Ms. Albino’s home, so the health and economic fate of her and thousands of others here rest on the corporate maneuvers he is carrying out.

La Oroya has been called one of the world’s 10 most polluted places by the Blacksmith Institute, a nonprofit group that studies toxic sites. But for several months, the Peruvian smelting company in Mr. Rennert’s empire has claimed that low metals prices prevented it from completing a timely cleanup to lower the emissions that have given this town such an ignoble distinction.

The tensions here over the lead emissions and the smelter’s financial meltdown is precisely the kind of dire mix of foreign investment and environmental contamination feared by indigenous groups elsewhere in Peru, particularly in the country’s Amazon basin, where protests over similar issues left dozens dead this month.