Graduation Year

2023

Document Type

Thesis

Degree

M.S.P.H.

Degree Name

MS in Public Health (M.S.P.H.)

Degree Granting Department

Public Health

Major Professor

Thomas E. Bernard, Ph.D., CIH

Committee Member

Steven Mlynarek, Ph.D., CIH

Committee Member

Renè R. Salazar, Ph.D., CIH

Keywords

Aluminum Smelter, Exposure Limit, Heat Index, Heat Related Illness

Abstract

Introduction: Heat stress is clearly associated exertional heat illnesses (EHI) in workers in a number of studies. With expected increase in extreme thermal changes, an increase understanding the effects of heat stress conditions is necessary. The purpose of this study was to compare heat stress levels in a manufacturing plant to determine whether a relationship exists between heat stress level relative to the occupational exposure limit and exertional heat illness incidents.Methods: OSHA recordable heat illness cases (n=35) were collected over a three year period. Over the same period, hourly ambient Heat Index data was collected. For this manufacturing plant, heat stress assessments based on the wet bulb globe temperature were related to the ambient HI. This allowed characterization of the hourly heat conditions above the occupational exposure limit (OEL). The incidence of EHI was calculated by finding the number of OSHA recordable cases 0.5 °C-WBGT increments. The denominator is the total hours in the same increment. A Poisson regression was completed that related the incidence rate of EHI’s to the elevation above the OEL.

Results: Results indicated a significant relationship of the incidence rate of EHI’s in relation to exposure at the OEL (Incidence = e(-5.94 + 0.34 ∆OEL)). The Rate Ratio (RR) was 1.4 / °C-WBGT. Findings also indicated some cases occurred between the action limit (AL) and the OEL, and a steady exponential increase above the OEL.

Conclusions: This study demonstrated that heat related illnesses are related to the heat stress levels based on the OEL. Findings also indicated an emphasis of exercising caution for workers exposed to conditions below the OEL but above the action limit.

Download

Share

COinS