Health Hazard Evaluation Report: HETA-2001-0279-3163, September 2012. Evaluation of Air Sampling Methods for Abrasive Blasting - Louisiana.

摘要

NIOSH received a request for an HHE from the management at a Louisiana shipyard to evaluate sampling methods for measuring employee PBZ exposures during abrasive blasting. On July 20, 2001, NIOSH investigators collected side-by-side PBZ air samples using three types of commercially available sampling devices: a closed-face 37-mm cassette, an unshielded BAS, and a shielded BAS. For each type of sampling device we collected an 'active' PBZ sample that was connected to an air sampling pump and a 'passive' PBZ sample that was not connected to an air sampling pump. These active and passive samples were collected side-by-side for the duration of the abrasive blasting activity (approximately 60 to 80 minutes). Samples were used to evaluate whether inertia-driven abrasive material could enter the sampler during abrasive blasting. All of the air samplers were positioned outside the employees' abrasive blasting helmet following OSHA sampling guidance. Total dust was measured for the 37-mm filter samples. Inhalable dust was measured for the unshielded and shielded BAS samples. The harsh and dusty abrasive blasting environment caused frequent sampling pump failures. Because of the failures, there was insufficient data for a statistical comparison of the air sampling results for the three sampling methods. All 37-mm cassette samples contained inertia-driven (loose) abrasive grit particles that accounted for up to 99% of the total particle weight. All unshielded and shielded BAS samples contained loose particulate. BAS total weights exceeded the recommended maximum sample loading of 2 mg. Some of the passive samples collected a similar amount of particulate as the active samples. We concluded that none of the sampling methods we used performed reliably in an abrasive blasting environment. All were likely to overestimate air concentrations because of the presence of inertia-driven particulate in the samplers. Improving the design of sampling devices or developing alternative sampling methods is needed to accurately and reliably assess PBZ dust exposure concentrations during abrasive blasting operations.