LOS ANGELES (Reuters) - Soil testing at 500 homes surrounding the now-shuttered Exide Technologies battery recycling plant near Los Angeles found all but a handful of dwellings with lead contamination at levels requiring cleanup, public health officials reported on Tuesday.

The finding, presented to the Los Angeles County Board of Supervisors, adds to previous sampling by the state Department of Toxic Substances Control showing more than 200 other homes near the Exide plant with lead-tainted soil in need of removal.

The state and county ultimately plan to test soil at some 10,000 properties in communities surrounding the plant, which Georgia-based Exide agreed last March to close permanently to avoid criminal prosecution for illegal storage of hazardous waste.

Exide, which filed for Chapter 11 bankruptcy protection in 2013, also has agreed to pay $50 million toward the cost of the cleanup, one of the biggest such efforts ever undertaken in the state.

But community activists and local politicians have complained that the pace of remediation has been too slow.

Governor Jerry Brown called in February for spending an additional $176.6 million to speed up and expand testing and cleanup around the defunct battery recycling site, located in the municipality of Vernon, just east of Los Angeles.

The state’s toxic substances department has estimated that deposits of lead dust from the Exide plant extend into neighborhoods lying within 1.7 miles of the facility, and that as many as 2,500 homes - up to a quarter of the homes within that radius - will eventually require cleanup.

Of nearly 500 homes where tests last month showed excessive amounts of lead in the soil, 45 had traces of the toxic metal at concentrations considered hazardous waste pollution, the County Public Health Department said in a summary of its findings.

A separate analysis issued days earlier found blood lead levels in young children living near the Exide plant were higher than those living farther away, though the greater prevalence of older housing closer to the facility appears to account for some of the difference.

Exposure to lead is known to put children at greater risk of brain and nervous system damage, learning disabilities and other developmental problems.

The plant, which melted down and recycled lead-acid batteries, had been operating for several decades when it was taken over by Exide in 2000.