Diesel particulate: it matters

According to reports from the field, the Mine Safety and Health Administration has begun enforcing an exposure limit of 160 micrograms of total carbon (TC) per cubic meter of air (160TC µg/m3) and said it has developed a practical sampling strategy to account for interferences from non-diesel exhaust sources when TC is used as a surrogate for measuring a miner's exposure to diesel particulate matter (DPM). The limit applies to underground metal and nonmetal mines.

The limit has been 350TC. MSHA measures a miner's personal exposure to DPM by analyzing a sample for TC, which is a DPM surrogate obtained by combining elemental carbon (EC) and organic carbon (OC). In its May 2006 DPM final rule, MSHA said it would propose a rule to convert the 160 TC PEL to a comparable EC PEL prior to the effective date of May 20, 2008, if sufficient scientific data were available to support a proposed rule. But MSHA chose not to issue the proposed rule, instead offering a protocol for calculating a location-specific adjustment for situations in which the EC on the miner's personal sample is less than 160 micrograms per cubic meter of air times the error factor for EC, and TC on the miner's personal sample is greater than 160 micrograms per cubic meter of air times the error factor for TC. MSHA said it believes there is still insufficient evidence suggesting an appropriate conversion factor. Read the entire article here. Your comment?

Award winner

Pit & Quarry columnist Ellen Smith's Mine Safety and Health News has received the Sigma Delta Chi Award from the Society of Professional Journalists for Public Service in Newsletter Journalism for coverage of the Sago Mine Disaster. The Sigma Delta Chi Awards date back to 1932, when the Society first honored six individuals for contributions to journalism. The current program began in 1939, when the organization awarded the first Distinguished Service Awards. These awards later became the Sigma Delta Chi Awards. Mine Safety and Health News staff, Ellen Smith, Melanie Aclander and Kathy Snyder will be presented with their award July 20 during the annual Sigma Delta Chi Awards banquet at the National Press Club in Washington, D.C. “These awards represent the best of American journalism,” said SPJ President Christine Tatum. “In an age when it is increasingly difficult to differentiate between fact and opinion and news and entertainment, the outstanding work of these journalists is a powerful reminder of the importance of ethical and responsible news gathering that is of true public service. This award winning work is what all journalists should strive to deliver every day.” Congrats to Ellen and her fine staff. Your comment?