Visiting Thursday, Friday and Saturday at dinnertime, the researchers took sound readings for several one-hour periods and calculated the average noise exposure workers might get in an eight-hour stretch.
Two high-, four intermediate- and four low-DMF exposure workers from a synthetic leather factory were monitored in airborne DMF concentrations and N-methylformamide (NMF) concentrations in urine across four consecutive days.
But a new study raises concerns about even very low levels of exposure: Workers in Chinese shoe factories who inhaled less than 1 part per million (ppm) of benzene--an exposure considered safe under U.S. occupational guidelines--had fewer white blood cells than did unexposed workers.
Brooks said risk managers didn't think an extra uncertainty factor was necessary and that scientists had overestimated the exposure workers would receive.
In experiment 3 (unilateral antennal exposure), workers' antennae were inserted into two capillaries, similarly to experiment 2, but one capillary was coated with colony-specific CHCs and the other with solvent only (sham treatment).
Irrespirable particulate exposures were measured on a subset of high exposure workers.
