A United Nations expert is warning that Mexico is facing a “toxic crisis” driven in part by the United States’ use of its southern neighbor as a waste disposal site. Marcos Orellana, the U.N. special rapporteur on toxics and human rights, conducted an 11-day investigative mission in Mexico, finding that weak environmental regulations and a lack of oversight have allowed pollution to accumulate, turning communities into what he called “sacrifice zones.” Government records show the U.S. exports hundreds of thousands of tons of hazardous waste to Mexico each year, including lead-acid car batteries. Meanwhile, Mexico has increased imports of waste to be burned as cheap fuel for industry. Orellana said the result is the “legalized poisoning of people.”