Environmental factor – June 2022: GuLF study describes inhalation and dermal exposures for all hydrocarbon cleaning stations
In a just-published monograph, researchers from the NIEHS Gulf Long-term Follow-up (GuLF) study describe the extraordinary work that has gone into developing inhalation and dermal exposure estimates for people involved in oil spill response and cleanup after the 2010 Deepwater Horizon oil spill. the Gulf of Mexico. The GuLF study follows these workers over time to assess potential short- and long-term health effects.
The articles included in the monograph describe the statistical and methodological bases of the exposure estimates that have been developed. The scientists highlight approaches to dealing with large amounts of missing data, data sources used to generate estimates, and theoretical models that have been developed to describe exposures that could not be directly measured. The reports include exposure levels of six components of crude oil and fine particulate matter (PM2.5) produced by the combustion and flaring of oil and natural gas. The work is the result of 10 years of research.
“This was the largest oil spill in the United States, and no oil spill study has ever undertaken an exposure assessment project as large as ours,” said Dale Sandler, Ph.D., principal investigator and head of the epidemiology branch of the NIEHS, who is leading the study. “This is a monumental achievement by our exposure assessment team.”
For example, researchers found that workers on all vessels associated with oil rig, firefighting, research and other on-water operations had some level of exposure to benzene compound, a known carcinogen.
With information about the most vulnerable job roles, those responsible for oil spill cleanup jobs can better plan how to protect workers from similar exposure scenarios, said Kaitlyn Lawrence, Ph.D., scientist from the NIEHS Chronic Disease Epidemiology Group. She began working on the GuLF study in 2014 as a summer intern, and under Sandler’s mentorship, she completed her doctoral dissertation on the impact of oil spill exposures on lung function in using data from the GuLF study.
Now, exposure methods and results will be available to researchers and policymakers in a single publication, Sandler said. The monograph is published in the journal Annals of Work Exposures and Health.
Quantification of exposure risks
The GuLF study was a national effort led by the NIEHS to determine whether the Deepwater Horizon spill caused any physical or mental health issues among responders.
Measured in a changing landscape of ad hoc response and cleanup work, exposure assessment breaks new ground by quantifying worker exposures following a massive industrial disaster, Lawrence said.
“It would be difficult to find this level of detailed exposure assessment following exposures to work-related disasters of any type,” Lawrence added. “This monograph should be considered a blueprint for any future similar efforts in industrial hygiene.”
In the years following the Deepwater Horizon disaster, workers who participated in the cleanup effort were at increased risk of developing hypertension, also known as high blood pressure. They also experienced mental health issues, such as post-traumatic stress disorder and depression; decreased lung function; heart disease; and a range of symptoms consistent with the effects of neurological and respiratory diseases, according to previous articles resulting from the GuLF study.
The new exposure data will allow GuLF researchers to answer questions “about the health risks associated with specific crude oil components known to be hazardous, filling a major gap in the literature,” Lawrence said.
Develop new statistical methods
The research team adapted industrial hygiene techniques to define exposure groups based on information about inhalation and dermal contact exposures to petroleum components over different time windows during the cleanup effort. The assessments took place over a wide geographic area in the Gulf of Mexico and along the coast of five Gulf States. Worker exposure varied by weather and location, and over time. The health effects also depended on the tasks and working time of the responders.
In addition, the scientists used statistical methods that allowed them to assign exposure levels to all workers participating in the GuLF study. To do this, they combined air exposure measurements taken at the time of the spill, the team’s modeling of unmeasured exposures at the time of the spill or afterwards, and individual descriptions of their duties related to the spill. cleaning, according to Sandler.
Oil spills around the world
With a continued need for oil cleanup operations around the world as accidents occur, many people may be exposed during cleanup efforts. Data from the United States National Oceanic and Atmospheric Administration Intervention and restoration office show that the office responded to 139 incidents in the first 10.5 months of 2021.
Of those cases, 108 were classified as involving oil. Many were small incidents, but some were larger spills — such as the California Coast Expo on October 2, 2021, which involved more than 140,000 gallons of crude oil. Although media coverage following many of these spills often focuses on the effects on wildlife, workers are still there to respond and potentially be exposed, Sandler said. She added that due to the scale and unprecedented scale of the Deepwater Horizon oil spill, the media paid particular attention to the exposure and health issues of those affected by the disaster, which which partly motivated the GuLF study.
Quote: Stewart P, Groth CP, Huynh TB, Gorman Ng M, Pratt GC, Arnold SF, Ramachandran G, Banerjee S, Cherrie JW, Christenbury K, Kwok RK, Blair A, Engel LS, Sandler DP, Stenzel MR. 2022. Assessment of Exposures from Deepwater Horizon Oil Spill Response and Cleanup. Ann Work Expo Health 66 (Supplement_1):i3–i22.
(Catherine Arnold is a contract writer for the NIEHS Office of Communications and Public Liaison.)