The Environmental Protection Agency announced Monday that it has reached a settlement with two school bus companies regarding excessive diesel idling.

Both companies, Ocean State Transit and STA of Connecticut, are subsidiaries of Student Transportation of America, which has a fleet of 7,500 school buses in 16 states. Field testing that was the basis of EPA's claims of excessive idling, which exposes children to diesel pollution, was conducted in several communities including Groton, which is still served by STA of Connecticut.

Under the settlement, the companies will pay a $35,000 penalty and will commit to reduce idling from its fleet by performing environmental projects valued at $131,000, the EPA said in a news release.

EPA said that in the fall of 2011, it observed school buses idling for extended periods in East Greenwich and South Kingstown, R.I., and in Danbury, Naugatuck, Higganum, Stamford and Groton. Some buses idled for more than 30 minutes before the buses left the lot to pick up schoolchildren, EPA said. The state idling regulations in question, which are enforceable by EPA, generally limit idling in Connecticut to three minutes and in Rhode Island to five minutes.

Under the settlement, the companies will implement a national training and management program to prevent excessive idling from the company's entire fleet of school buses. Drivers, dispatchers and managers will be trained to comply with state and local anti-idling regulations and to avoid excessive idling, and all supervisors to monitor idling in school bus lots. The company will also post anti-idling signs where drivers congregate, and will notify the school districts it serves of its anti-idling policy.

In addition, STA of Connecticut will replace nine older school buses with new buses that are equipped with state-of-the-art pollution controls, and Ocean State will install GPS units and tracking systems on 117 of its buses to facilitate tracking and eliminate excessive idling.

Idling diesel engines emit pollutants which can cause or aggravate a variety of health problems including asthma and other respiratory diseases, and the fine particles in diesel exhaust are a likely human carcinogen, EPA said. Diesel exhaust not only contributes to area-wide air quality problems, but more direct exposure can cause lightheadedness, nausea, sore throat, coughing, and other symptoms. Drivers, schoolchildren riding on the buses, facility workers, neighbors and bystanders are all vulnerable.

For information, visit: http://www.epa.gov/otaq/diesel/index.htm.