The federal Office of Surface Mining (OSM) oversees the regulation of coal mining by the Pennsylvania Department of Environmental Protection (PADEP), which performs most inspections of coal mines in the state. Occasionally, OSM inspectors accompany their state counterparts on what are known as "oversight inspections."

For each of the last three years, the joint federal-state oversight inspections have cited about 110 violations for each 100 inspections of Pennsylvania coal mines. When state inspectors work alone, however, they cite fewer than five violations per 100 inspections.

This startling discrepancy is revealed by OSM's last three annual evaluation reports on Pennsylvania's coal mine regulation program, which may be found on OSM's website: http://www.arcc.osmre.gov/Divisions/PFD/PA/AR/PA-AR.shtm. The recently released report for Evaluation Year (EY) 2011, which covers the period July 1, 2010 through June 30, 2011, continues analyses of violation statistics OSM began in EY2009.

In each report, OSM first focuses on the specific coal mines where it conducted oversight inspections with PADEP during that evaluation year. OSM compares the number of violations cited during the joint OSM-PADEP oversight inspections with the number of violations PADEP had cited when it alone inspected the same mines, during the preceding six months. Here are the numbers as reported by OSM:

The upshot is that on the very same mine sites where PADEP inspectors had cited just 132 violations during the preceding six months, joint oversight inspections by OSM and PADEP found 605 violations. For many of these mines, PADEP was required to conduct six (monthly) inspections during the six-month period preceding the oversight inspection.

OSM's reports also examine the violation rate, that is, the average number of violations cited per inspection. OSM compares the rates at which PADEP inspectors cite violations when acting alone versus when they are accompanied by their OSM counterparts on oversight inspections. Here are the violation rates as reported by OSM:

The figures in the last column show that the number of violations per inspection is between 27½ and 55 times higher when OSM inspectors accompany PADEP inspectors than it is when PADEP inspectors are on their own. Combining OSM's raw data for all three years, the rate of 1.1 violations per oversight inspection is 36.7 times higher than the rate of 0.03 violations per PADEP inspection. Even if the "PADEP-Only" violation rate is calculated by dividing the violations cited on all inspections (both "complete" and "partial") by the number of complete inspections, the violation rate for oversight inspections is still 12.2 times higher than the rate of 0.09 violations per complete PADEP inspection.

Oversight inspections, unfortunately, are comparatively rare. During each of the last three evaluation years, they made up only 2 to 5 percent of the total number of complete inspections at Pennsylvania coal mines. Although that small percentage had been increasing, OSM's most recent report notes that during EY2011, retirements had reduced the number of OSM inspectors assigned to Pennsylvania from five to just three, with the two vacancies still unfilled at the end of the evaluation year.

In an ideal world, of course, the violation rates for both state-only and federal-state oversight inspections would be zero. In the real world, the persistent and enormous differences in violation rates revealed by OSM's evaluation reports suggest that thousands more violations at Pennsylvania coal mines would be detected and cited each year if OSM could participate in every inspection.

In light of the violation data, the most important number in the most recent OSM report may be "two" — the number of OSM inspector vacancies that remained unfilled at the end of EY2011. If those positions have not been filled already, we hope they will be very soon.