LOS ANGELES — It’s been called the largest environmental disaster on the West Coast. More than 10,000 properties in Boyle Heights, over the span of almost a century, were blanketed with toxic chemicals like lead that were released into the air by a nearby battery recycling plant.

California's Department of Toxic Substances Control has cleaned up more than 4,700 homes in the last few years, but residents say that's not enough. Some are now asking for the federal government to get involved.