Date of Award

Summer 2015

Degree Type

Non-Thesis Project

Degree Name

Master of Science (MS)


Industrial Hygiene

Committee Chair

Julie Hart

First Advisor

Terry Spear


No worker should have to suffer a life altering or fatal illness for the sake of a job, yet thousands of workers have died or developed a disabling illness from occupational exposure to silica. The Occupational Safety and Health Administration (OSHA) has not updated the permissible exposure limit (PEL) for silica since 1971. The current PEL for respirable crystalline silica in the construction industry is 250 mppcf/ (%SiO2 + 5) TWA which is adjusted per the amount of silica in the sample. This exposure limit is known to cause silicosis, a disease developed from silica exposure. The construction industry uses multiple processes and materials that contain and generate hazardous silica dust. OSHA has proposed a silica standard that reduces the PEL and provides ancillary provisions to protect the health and safety of workers.

Engineering controls are proven to reduce the exposure of silica during certain construction activities. The OSHA has developed a table titled ‘Exposure Control Methods for Selected Construction Operations’ which lists controls that can be used to certain silica generating activities. In the proposed standard, the control methods in this table can be followed in place of sampling.

Personal exposure monitoring was conducted to determine the effectiveness of engineering controls on certain silica-generating activities listed in OSHA’s table ‘Exposure Control Methods for Selected Construction Operations.’ Eight out of 10 (80 %) of the samples collected in this pilot study revealed crystalline silica exposures below the proposed PEL and 2 samples (20 %) revealed both sample weighted and 8 hour time weighted average concentrations above the proposed PEL. While the number of samples in this pilot study are limited, these results suggest that further evaluation should be performed to ensure workers in the construction industry are adequately protected.


A report submitted in partial fulfillment of the requirements for the degree of Industrial Hygiene