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New Data Study: Does Precipitation Impact A State’s Construction Injury Rates?

Blog Posts | Construction Safety

It is no secret that careers in the construction industry are more dangerous than other professions due to many adverse conditions that workers are exposed to. Narrowly avoiding traffic, slip and fall accidents, and electrocutions are a few potential hazards that construction workers face head-on. There are many factors that lead construction workers to be more prone to injury and/or death. In their study "States With Low Non-Fatal Injury Rates Have High Fatal Injury Rates and Vice-Versa," John Mendeloff and Rachel Burns cited that fewer unionized jobs, lower wages, and the scope of benefits in each state’s workers’ compensation program are causes for high fatal injury and low non-fatal injury rates.

Yet, there is one factor that hasn’t been looked at yet: rainfall. Wet conditions, according to OSHA, can lower the resistance skin has to electricity and can lead to more electrocutions. Wet ladders, roofs, and floors can also lead to slip and fall deaths as well. These two factors are the first and third leading cause of death for construction workers.

In fact, 38% of the 991 fatalities in the construction worker industry in 2016 were from slip and falls. To analyze whether precipitation is truly a factor in construction injury and death, we’ll compare the average annual precipitation from a thirty-year average between 1970 and 2000 with average annual precipitation in 2016 to determine if there are states that have seen more precipitation in recent years and if the fatality rate has gone up in tandem. This article will also compare the number of construction workers that work in each state in order to calculate a fatality rate for each state to determine if there is any correlation between a higher or lower fatality rate and the state a construction worker works in. Annual mean wage will also be a variable that is explored. This article is using data that has been pulled from the Bureau of Labor Statistics and the Southern Regional Climate Center to be able to compare the state fatality rate in 2016 and the state average annual precipitation in 2016.

Average Annual Precipitation in 1970 vs. 2016

From 1971 to 2000, states with the highest average annual precipitation in the country tended to be in the southeastern United States. The thirty-year average for Louisiana, Alabama, Tennessee, Georgia, and Arkansas was between 50 and 60 inches of rainfall. These states averaged 60.1, 58.3, 54.2, 50.7, and 50.6 inches of rainfall per year, respectively.

Five states that had some of lowest annual precipitation averages between 1971-2000 in the United States included Nevada (9.5 inches), Arizona (13.6 inches), California (22.6 inches), Utah (12.2 inches), and Wyoming (12.9 inches). When you compare these figures to the average annual precipitation in 2016, there are a few differences.

The five states with the highest average annual precipitation include Louisiana, Florida, Mississippi, North Carolina, Arkansas, and Kentucky. On the flip side, five states with the lowest average annual precipitation in inches includes Nevada (11.5), Arizona (12.3), New Mexico (12.9), Utah (13.5), and Colorado (17.08).

When you look at the amount of rain each state got from 1971-2000 and 2016, there aren’t many states where there was noticeably more precipitation in 2016. Idaho is one case, where there was 18.4 between 1971 and 2000, and 24.88 inches in 2016. Minnesota received 6 more inches of rain in 2016 (33 inches) versus 27 inches between 1971 and 2000. Alabama saw noticeably less precipitation in 2016 (45 inches) versus 58 inches between 1971 and 2000. Outside of a few outliers, there wasn’t a strong trend with a lot of states receiving more precipitation that can be correlated with an increasing fatality rate in the construction industry.


The number of employees in each state that work in the construction industry was retrieved from the Bureau of Labor Statistics to see if labor force population differences between each state is correlated with the number of construction industry fatalities in that state.

Average annual precipitation in each state came from the Southern Region’s Climate Center. The source of annual mean wage is from the Bureau of Labor Statistics. Both of these variables were put into a regression in order to see if they correlated with the fatality rate and to see if they are statistically significant. The primary reason for calculating a fatality rate and running it against average annual precipitation and annual mean wage was because the Bureau of Labor did not record whether an electrocution, slip and fall, or impact by a sharp object were due to weather conditions. If this was the case, this study would have recorded the number of fatalities due to weather conditions and the results may have been vastly different.


The Construction Labor Force/Number of Fatalities Regression shows how much labor force population impacts the number of fatalities that occur in the construction industry on a state by state basis. The number of fatalities that occur in a given state is very dependent, as you might guess, on the number of construction workers that are employed in a given state. The r square is .82, which means that 82% of the fatality rate in a given state can be correlated with labor force population.

The regression that tested whether precipitation was correlated with the fatality rate showed that precipitation has no correlation with the rate of fatalities in each state.

The regression that ran annual mean wage against fatality rate has an r square of .10, which means that 10% of the fatality rate can be correlated with annual mean wages. Correlation should never be confused with causation, but it looks like labor force population has a very large impact on fatality rate in each state and that annual mean wage is also a variable to consider when looking at fatalities in the construction industry. Precipitation was not correlated with the fatality rate.

Overall, the number of fatalities in the construction industry is strongly correlated with the number of workers in a given state. There is a weak correlation between annual mean wage and fatality rate. Due to the data restraints that made segregating between weather and non-weather-related fatalities unfeasible, this is an imperfect study and should be treated as such. With that said, labor force population is a variable that is correlated with the number of fatalities that occur in a given state whether you are working in the construction industry or as a utility linesman. The number of workers in the construction industry should not be considered as a cause of death. There is, however, a strong trend between states that have high labor force populations and states that have a high number of fatalities.

About The Author

The data analysis and reporting for the precipitation study were conducted by the attorneys at Electrocution Lawyers, PLLC. For over 30 years, the firm has been dedicated to helping prevent shock injuries on the job.