Federal officials levied about $1 million in penalties against Chemical Waste Management for failing to properly dispose of waste near a community known for a rash of birth defects.
Chemical Waste Management is the operator of the largest toxic dump in the West.
The settlement comes after the U.S. Environmental Protection Agency found that the company's lab equipment was improperly set for more than five years and therefore unable to detect accurate concentration levels of hazardous chemicals.
Inspectors say there is no evidence these latest violations pose any health threat to the community or workers at the dump site.
The company will have to pay a $400,000 fine and spend an estimated $600,000 to replace its laboratory equipment, software and procedures.
Federal regulators also have ordered the waste company to use an outside lab for at least two years to verify that its hazardous wastes meet treatment standards prior to disposal.
The Associated Press contributed to this report.