Allison Morantz (Stanford) has an interesting paper, Coal Mine Safety: Do Unions Make a Difference?, in the current Industrial and Labor Relations Review, Vol. 66:1 (Jan. 1, 2013). The paper draws from UMWA data and finds that increased unionization correlates with a decrease in serious worker injuries, but an increase in nontraumatic worker injuries. Perhaps even more interesting, however, is the potential effect of unionization on worker injury reporting. The abstract follows.
"Although the United Mine Workers of America (UMWA) has always advocated strongly for miners' safety, prior empirical literature contains no evidence that unionization reduced mine injuries or fatalities during the 1970s and 80s. This study uses a more comprehensive dataset and updated methodology to examine the relationship between unionization and underground, bituminous coal mine safety from 1993 to 2010. I find that unionization predicts a substantial and significant decline in traumatic injuries and fatalities, the two measures that I argue are the least prone to reporting bias. These disparities are especially pronounced among larger mines. My best estimates imply that overall, unionization is associated with a 13-30% drop in traumatic injuries and a 28-83% drop in fatalities. Yet unionization also predicts higher total and nontraumatic injuries, suggesting that injury reporting practices differ between union and nonunion mines."