Airborne Silica Exposure Assessment

Specialty Consulting, Inc. (SPC) was engaged by Day & Zimmerman to conduct a respirable crystalline silica (RCS) exposure assessment. The objective was to evaluate worker exposure to airborne silica during activities in the hopper building, ensuring compliance with the new OSHA standard for RCS, which mandates protection from exposures above the permissible exposure limit (PEL) averaged over an eight-hour day.

SPC conducted silica dust sampling and analysis following the National Institute for Occupational Safety and Health (NIOSH) Method 7500. This involved drawing representative air through pre-weighed membrane filter, housed in a closed-face cassette. Samples were collected from workers most likely to be exposed, representing each step of the work process: runners on the 4th-floor platform, pull and drop operators, hopper workers on the 1st floor, cutters separating materials, and individuals loading new cages outside the hopper building.

These workers' activities included replacing cages and bags in the hoppers from the 4th to the 1st floor. SPC's comprehensive assessment revealed exposure levels and provided actionable recommendations. SPC advised the implementation of engineering and administrative controls and the use of personal protective equipment (PPE) to mitigate RCS exposure. This approach ensured that worker safety was prioritized while maintaining compliance with regulatory standards.