Lead can damage the nervous system, kidneys and reproductive system, according to the federal Agency for Toxic Substances and Disease Registry.
Lead wheel weights are clipped to the rims of every automobile wheel in the United States to balance tires, according to the U.S. Environmental Protection Agency.
Weights often fall off tires, entering storm sewers and waterways or winding up in municipal landfills after street cleaners collect them, according to the EPA.
No regulatory controls govern the use of lead wheel weights, according to the EPA.
But small particles from traffic-worn wheel weights are a small source of lead compared with lead that falls from the sky and leaded paint residue, according to the state Department of Environmental Protection study.
And the amount of lead released via wheel weights appears likely to decline because of legislation, voluntary phase-outs and new wheel technology, the study says.
A National Lead Free Wheel Weight Initiative encourages a move to lead-free alternatives, according to the EPA.