Pit & Quarry, February 2015

SAFETY Silica safety Understanding dust sources to support healthier work practices BY EMILY J HAAS AND ANDREW B CECALA E xposure to silica and other respirable dust continues to be a health hazard for workers in the aggregates industry When tracking exposure by job classification bag machine operators and bag stackers are consistently at the top of the list of individuals exposed to dust on the job The National Institute for Occupational Safety Health NIOSH sought to understand the daily risks that workers encounter because of overexposure to silica dust NIOSH also investigated how these workers perceived the risks and what behaviors they practiced to minimize silica dust exposure Reducing silica exposure Minimizing sources of silica and other respirable dust is a priority in the mining industry Willingness from mine sites to collaborate on research efforts and purchase new equipment has helped improve and develop new dust control methods For example NIOSH engineering technologies has been tested in cooperation with mine sites and has significantly reduced mineworkers exposure to respirable silica while performing job tasks through implementing new equipment and research Another important issue is whether the Mine Safety Health Administration MSHA adopts the Occupational Safety Health Administrations OSHA proposed respirable silica dust standard which would reduce the allowable level from 100 to 50 micrograms per cubic meter If the allowable level changes the mining industry will face a significant increase in the number of workers whose dust levels exceed the allowable limit Despite industry efforts to reduce dust exposure data continues to show that certain occupations have consistently higher overexposure rates to silica however individual work practices that can help reduce respirable dust sources are increasingly important to help companies comply with regulatory standards Baggers perceived dust risks and response Workers perception of risk on the job is a primary indicator of their health protective attitudes In general if people see themselves at greater risk for injury or disease they are more likely to make safe Baggers at aggregate operations should take steps to reduce exposure to silica and other respirable dust choices NIOSH researchers interviewed baggers to gain an understanding of their job tasks and what behaviors might expose them to higher quantities of silica dust NIOSH talked to baggers at one plant with an automated bagging system and another plant without an automated bagging system that required five workers to rotate tasks throughout the day to complete bagging jobs NIOSH noticed several trends among the workers interviewed Knowledge of dust sources and exposure When asked about primary health and safety hazards on the job baggers consistently said that dust exposure is their main risk Baggers tended to be knowledgeable of the job tasks that produced the most dust They also overwhelmingly indicated that some of these tasks were their least favorite These job tasks included sealing bags standing at the bagger and cleaning up a broken bag Baggers also noted they are more aware of dust exposure if they see it in the air particularly when sunlight shines into the facility One bagger explained that even though they know about the dust when its non visible seeing it is a good reminder of its presence prompting workers to wear respirators Education on hazardous dust exposure in the workplace could improve workers health with time 54 PIT QUARRY February 2015 www pitandquarry com