Heat and Worker Health

Interest in the effect of hot temperatures on health and productivity continues to mount as global temperatures rise due to climate change. Because many jobs require workers to be outside, workers face unique risks from extreme weather. Despite workers’ health risks and despite the fact that research typically finds large effects of average temperatures on aggregate productivity, little research has used daily data to examine what hot days do to workers.

The main goal of this paper is to shed light on the effect of high temperatures on workers’ health and productivity. I seek to examine the point at which higher temperatures compromise workers’ health and to test for nonlinearities in the health effects of high temperatures. I also seek to examine if consecutive hot days or temperature shocks are worse for workers’ health than if temperatures gradually rise. Since workers may have more control over avoidance efforts and may be more likely to report heat-related illnesses when unemployment rates are low, I also test for heterogeneity based on unemployment rates. A secondary goal of this study will be to examine the effect of hot days on various measures of productivity.  

The primary analysis for this paper draws on daily weather data from the National Climatic Data Center matched to daily medical data on work-related medical conditions from Texas workers’ compensation claims from 2005 to 2012. Texas is ideal for studying the effects of high temperatures. In addition to many parts of Texas having high temperatures, Texas’s size means that different parts of the state can experience substantially different weather than other parts on any given day. I estimate models that control for day and county fixed effects with various county-level measures of heat-related illnesses as dependent variables.

I also plan on supplementing the analysis with daily data on OSHA safety inspections. Since following safety guidelines likely requires attention to detail, an establishment receiving more of certain types of fines would suggest workers are less attentive on hot days. I also hope to supplement these data with other data on productivity in Texas.

The initial results suggest that worker health is compromised at temperatures above 90 degrees. Once temperatures rise above 100 degrees, the effects become much more detrimental. I find no evidence that multiple consecutive hot days produce more severe health effects or that large temperature shocks are much more detrimental to worker health.

The estimates imply that an additional day between 100 and 104 degrees results in $250 more being spent on workers’ medical care per 100,000 people. An additional day between 105 and 109 degrees results in $500 more being spent on workers’ medical care per 100,000 people. An additional day higher than 109 degrees results in over $1,000 more being spent on workers’ medical care per 100,000 people.