The U.S. Environmental Protection Agency (EPA) has settled enforcement actions against two companies that violated state and federal clean air standards by allowing excessive idling of school buses at locations in four Massachusetts communities.

The first settlement resolved EPA's allegations that AA Transportation Co., Inc., of Shrewsbury, Mass. allowed excessive idling of school buses at three locations: two locations in Shrewsbury, and one in Webster, Mass. A separate settlement resolved EPA's allegations that Michael J. Connolly & Sons, Inc., of Walpole, Mass. allowed excessive idling of school buses at two locations, in Sharon, and Natick, Mass.

"Pollution from diesel-powered vehicles is a serious health concern for people throughout New England – that's why idling diesel school buses is unacceptable" said EPA New England Regional Administrator David W. Cash. "Children, especially those suffering from asthma or other respiratory ailments, are particularly vulnerable to diesel exhaust. We also know that chronic ailments are more likely for people living in historically disadvantaged neighborhoods and communities. Following existing rules to limit school bus idling helps protect the health of school children in communities across the country."

Idling diesel engines emit pollutants that 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. Diesel exhaust contributes to area-wide air quality problems, and more direct exposure can cause lightheadedness, nausea, sore throat, coughing, and other symptoms. Drivers, school children riding on the buses, facility workers, neighbors, and bystanders are all vulnerable.

AA Transportation will pay a $23,587 penalty, and Michael Connolly & Sons will pay a $28,500 penalty. Both companies have certified that they are now in compliance with federal and Massachusetts regulations limiting idling of vehicles. In both settlements, the companies agreed to implement various measures to promote compliance, including the use of GPS systems to track instances of excessive idling, modification of automatic shutoff timing systems to prevent excess idling, and increased driver awareness training.