Deepwater Horizon Explosion Research Articles

Sun may make oil stick atop cold ocean

New research suggests that oil spills in cold locations with lots of sun exposure could play out much differently than warm-water spills, such as the one that followed the Deepwater Horizon explosion in 2010. Last week at the ACS Spring 2023 meeting, Danielle Haas Freeman , a PhD candidate at Woods Hole Oceanographic Institution, detailed how sunlight-driven photooxidation could leave a larger-than-expected fraction of spilled oil suspended on the surface of cold water. “What that means is that you would have more oil to clean up, and then you’d also end up with potentially more oil reaching sensitive coastal ecosystems,” said Collin P. Ward , a geochemist at Woods Hole who led the study. Freeman and Ward looked at the physical properties governing two different pathways for oil to be removed naturally from the water’s surface: entrainment, a process in which oil gets broken up and drawn down into the

Assessing Exposures from the Deepwater Horizon Oil Spill Response and Clean-up.

The GuLF Study is investigating adverse health effects from work on the response and clean-up after the Deepwater Horizon explosion and oil release. An essential and necessary component of that study was the exposure assessment. Bayesian statistical methods and over 135 000 measurements of total hydrocarbons (THC), benzene, ethylbenzene, toluene, xylene, and n-hexane (BTEX-H) were used to estimate inhalation exposures to these chemicals for >3400 exposure groups (EGs) formed from three exposure determinants: job/activity/task, location, and time period. Recognized deterministic models were used to estimate airborne exposures to particulate matter sized 2.5 µm or less (PM2.5) and dispersant aerosols and vapors. Dermal exposures were estimated for these same oil-related substances using a model modified especially for this study from a previously published model. Exposures to oil mist were assessed using professional judgment. Estimated daily THC arithmetic means (AMs) were in the low ppm range (<25 ppm), whereas BTEX-H exposures estimates were generally <1000 ppb. Potential 1-h PM2.5 air concentrations experienced by some workers may have been as high as 550 µg m-3. Dispersant aerosol air concentrations were very low (maximum predicted 1-h concentrations were generally <50 µg m-3), but vapor concentrations may have exceeded occupational exposure excursion guidelines for 2-butoxyethanol under certain circumstances. The daily AMs of dermal exposure estimates showed large contrasts among the study participants. The estimates are being used to evaluate exposure-response relationships in the GuLF Study.

Estimation of Airborne Vapor Concentrations of Oil Dispersants COREXIT™ EC9527A and EC9500A, Volatile Components Associated with the Deepwater Horizon Oil Spill Response and Clean-up Operations.

The Deepwater Horizon (DWH) drilling unit explosion above the Macondo oil well on 20 April 2010 caused the release of approximately 4.9 million barrels (779 million L) of oil into the Gulf of Mexico. As part of a larger spill response and clean-up effort, approximately 1.84 million gallons (6.81 million L) of chemical dispersants COREXIT™ EC9500A and COREXIT™ EC9527A were applied to the resultant oil slicks through spraying on the water surface by plane and by vessel and through injection at the release source near the seabed. The GuLF STUDY is investigating the health effects of workers involved in the oil spill response and clean-up after the DWH explosion, and estimates of possible exposure to chemical dispersants were needed. Exposures were estimated to the volatile components of COREXIT™ EC9500A [petroleum distillates, hydrotreated light, and propylene glycol (PG)] and of COREXIT™ EC9527A [2-butoxyethanol (2-BE) and PG] using two of AIHA IHMOD2.0© mathematical modeling tools along with the dispersants' chemical and physical properties. Monte Carlo simulations were used to reflect uncertainty in input parameters with both the two-box, constant emission model and the near and mid field plume model for indoor and outdoor activities, respectively. Possible exposure scenarios considered various evaporation rates, sizes of the dispersant pool, wind speeds, and ventilation rates. For the two-box model, mean near field exposure estimates to 2-BE ranged from 0.9 to 5.7 ppm, while mean far field estimated exposures ranged from 0.3 to 3.5 ppm. Estimates of mean near field plume model exposures ranged from 0.01 to 3.7 ppm at 2.5 ft from the source, and <0.01 to 0.3 ppm at 10 ft from the source. Estimated exposures to PG were approximately 10% of the calculated 2-BE exposures and exposures to petroleum distillates about 40% higher than the 2-BE estimates. Results indicate that compared with current occupational exposure guidelines, overexposure to petroleum distillates and PG probably did not occur in our study, but under some conditions, for short periods, exposure to 2-BE may have exceeded the limits for peak exposures. These estimates were developed for use in job-exposure matrices to estimate exposures of workers having contact with dispersant vapors for the GuLF STUDY.

Summary of Findings and Research Recommendations from the Gulf of Mexico Research Initiative

Following the Deepwater Horizon explosion and oil spill in 2010, the Gulf of Mexico Research Initiative (GoMRI) was established to improve society’s ability to understand, respond to, and mitigate the impacts of petroleum pollution and related stressors of the marine and coastal ecosystems. This article provides a high-level overview of the major outcomes of the scientific work undertaken by GoMRI. This initiative contributed to significant knowledge advances across the physical, chemical, geological, and biological oceanographic research fields, as well as in related technology, socioeconomics, human health, and oil spill response measures. For each of these fields, this paper outlines key advances and discoveries made by GoMRI scientists (along with a few surprises), synthesizing their efforts in order to highlight lessons learned, future research needs, remaining gaps, and suggestions for the next generation of scientists.

From Disaster to Understanding: Formation and Accomplishments of the Gulf of Mexico Research Initiative

The Gulf of Mexico Research Initiative (GoMRI) was created in 2010 following the catastrophic Deepwater Horizon explosion and oil spill. BP engaged Rita Colwell to form and lead an independent board of experts to oversee an unprecedented program of scientific research on the effects of the spill. As a new and uniquely funded organization, GoMRI quickly developed and implemented a set of management processes, policies, and frameworks while simultaneously building an interconnected research community that eventually grew to nearly 4,500 individuals. The GoMRI Research Board and Management Team successfully produced and operated a system for requests for proposals, grants management, scientific and programmatic data management, and outreach and education, and assembled a scientific synthesis of results to create a lasting legacy 10 years after the disaster. Here, we document the challenges and key decisions underlying the design and operation of GoMRI as a model for independent, industry-funded research. In short, GoMRI represents a unique multi-sector partnership and a community of researchers that will advance science in the Gulf of Mexico and elsewhere for decades to come.

Polycyclic Aromatic Hydrocarbon-DNA Adducts in Gulf of Mexico Sperm Whale Skin Biopsies Collected in 2012.

The northern Gulf of Mexico has a long history of polycyclic aromatic hydrocarbon (PAH) contamination from anthropogenic activities, natural oil seepages, and the 2010 Deepwater Horizon explosion and oil spill. The continental shelf of the same area is a known breeding ground for sperm whales (Physeter macrocephalus). To evaluate PAH-DNA damage, a biomarker for potential cancer risk, we compared skin biopsies collected from Gulf of Mexico sperm whales in 2012 with skin biopsies collected from sperm whales in areas of the Pacific Ocean in 1999-2001. All samples were obtained by crossbow and comprised both epidermis and subcutaneous blubber. To evaluate exposure, 7 carcinogenic PAHs were analyzed in lipids extracted from Pacific Ocean sperm whale blubber, pooled by sex, and location. To evaluate PAH-DNA damage, portions of all tissue samples were formalin-fixed, paraffin-embedded, sectioned, and examined for PAH-DNA adducts by immunohistochemistry (IHC) using an antiserum elicited against benzo[a]pyrene-modified DNA, which crossreacts with several high molecular weight carcinogenic PAHs bound to DNA. The IHC showed widespread epidermal nuclear localization of PAH-DNA adducts in the Gulf of Mexico whales (n = 15) but not in the Pacific Ocean whales (n = 4). A standard semiquantitative scoring system revealed significantly higher PAH-DNA adducts in the Gulf of Mexico whales compared to the whales from the Pacific Ocean study (p = .0002).

Modeled Air Pollution from In Situ Burning and Flaring of Oil and Gas Released Following the Deepwater Horizon Disaster.

The GuLF STUDY, initiated by the National Institute of Environmental Health Sciences, is investigating the health effects among workers involved in the oil spill response and clean-up (OSRC) after the Deepwater Horizon (DWH) explosion in April 2010 in the Gulf of Mexico. Clean-up included in situ burning of oil on the water surface and flaring of gas and oil captured near the seabed and brought to the surface. We estimated emissions of PM2.5 and related pollutants resulting from these activities, as well as from engines of vessels working on the OSRC. PM2.5 emissions ranged from 30 to 1.33e6 kg per day and were generally uniform over time for the flares but highly episodic for the in situ burns. Hourly emissions from each source on every burn/flare day were used as inputs to the AERMOD model to develop average and maximum concentrations for 1-, 12-, and 24-h time periods. The highest predicted 24-h average concentrations sometimes exceeded 5000 µg m-3 in the first 500 m downwind of flaring and reached 71 µg m-3 within a kilometer of some in situ burns. Beyond 40 km from the DWH site, plumes appeared to be well mixed, and the predicted 24-h average concentrations from the flares and in situ burns were similar, usually below 10 µg m-3. Structured averaging of model output gave potential PM2.5 exposure estimates for OSRC workers located in various areas across the Gulf. Workers located nearest the wellhead (hot zone/source workers) were estimated to have a potential maximum 12-h exposure of 97 µg m-3 over the 2-month flaring period. The potential maximum 12-h exposure for workers who participated in in situ burns was estimated at 10 µg m-3 over the ~3-month burn period. The results suggest that burning of oil and gas during the DWH clean-up may have resulted in PM2.5 concentrations substantially above the U.S. National Ambient Air Quality Standard for PM2.5 (24-h average = 35 µg m-3). These results are being used to investigate possible adverse health effects in the GuLF STUDY epidemiologic analysis of PM2.5 exposures.

Epigenome-wide association study for transgenerational disease sperm epimutation biomarkers following ancestral exposure to jet fuel hydrocarbons

Jet fuel hydrocarbons is the generic name for aviation fuels used in gas-turbine engine powered aircraft. The Deepwater Horizon oil rig explosion created the largest environmental disaster in U.S. history, and the second largest oil spill in human history with over 800 million liters of hydrocarbons released into the Gulf of Mexico over a period of 3 months. Due to the widespread use of jet fuel hydrocarbons, this compound mixture has been recognized as the single largest chemical exposure for military personnel. Previous animal studies have demonstrated the ability of jet fuel (JP-8) exposure to promote the epigenetic transgenerational inheritance of disease susceptibility in subsequent generations. The diseases observed include late puberty, kidney, obesity and multiple disease pathologies. The current study is distinct and was designed to identify potential sperm DNA methylation biomarkers for specific transgenerational diseases. Observations show disease specific differential DNA methylation regions (DMRs) called epimutations in the transgenerational F3 generation great-grand-offspring male rats ancestrally exposed to jet fuel. The potential epigenetic DMR biomarkers were identified for late puberty, kidney, obesity, and multiple diseases, and found to be predominantly disease specific. These disease specific DMRs have associated genes that were previously shown to be linked with each of these specific diseases. Therefore, the germline (i.e. sperm) has environmentally induced ancestrally derived epimutations that have the potential to transgenerationally transmit disease susceptibilities to subsequent generations. Epigenetic biomarkers for specific diseases could be developed as medical diagnostics to facilitate clinical management of disease, and allow preventative medicine therapeutics.

A novel nonlinear hyperspectral unmixing approach for images of oil spills at sea

ABSTRACTHyperspectral remote sensing is currently being used to detect and monitor marine oil spills that cause damage to the environment. However, nonlinear interactions of oil and water make it difficult to extract their fractional abundances from the spectral response. Improving the modelling of nonlinear hyperspectral mixtures, which is required for a thorough and reliable characterization of the materials in an image, remains a challenging yet fundamental task. This study proposes a new model that combines polynomial and trigonometric systems to understand the nonlinear effects of oil and water spectral response. Although the model is nonlinear, unmixing is performed by solving a linear problem, thus allowing fast computation. Compared to classic polynomial models, the details of nonlinear interactions are better expressed and quantified, and the reconstruction accuracy and endmember abundance estimation are improved for both synthetic and real datasets. Both the polynomial and trigonometric parts of the model play important roles in characterizing nonlinearities, with statistically linear dependence areas covering more than 90% and 30%, respectively, in oil spill images sampled after the Deepwater Horizon explosion. Analysis of the experimental results suggests that the proposed model provides an efficient and accurate unmixing method that can be used to help design oil spill response plans.

Transport of dispersed oil compounds to the seafloor by sinking phytoplankton aggregates: A modeling study

Up to 20% of the oil spilled as a result of the Deepwater Horizon explosion in the Gulf of Mexico in 2010 was deposited as degraded oil compounds on the seafloor. Much of that deposition was likely due to dispersed oil compounds having been integrated into fast-sinking aggregates, which transported it effectively to depth. Understanding the details of this oil transport mechanism, and predicting its potential magnitude, is important for the management and mitigation of future oil spills.The 1-D model described here simulates a) a diatom bloom and the resulting formation of aggregates via coagulation of cells, b) the scavenging of dispersed oil compounds by these aggregates as they sink through the water column, c) the degradation of diatom carbon and oil carbon during transit, and d) the ultimate deposition of aggregates and oil compounds to the seafloor. The model is parameterized using primarily field- and laboratory-collected data and the model results are compared to sediment trap data. Specifically, one large diatom sedimentation event observed shortly after the Deepwater well was capped was modeled. The comparison of simulation results to field data assesses the model’s ability to explain the observed sedimentation event and tests our understanding of the main mechanisms driving such an event.The model results indicate that diatom carbon and oil compounds captured in the trap were linked to a sedimentation event that reached peak intensity just before the trap was deployed. The model simulations predict the measured sedimentation rates of oil compounds and organic carbon reasonably well, indicating that the key mechanisms driving this process were captured by the model. In the baseline case, which simulates the sedimentation of a large Skeletonema bloom in late August 2010, about 10% of the dispersed oil compounds lingering in the water were deposited to the seafloor. The ability of a sinking diatom bloom to scavenge dispersed oil compounds from the water column and deposit them to depth is a robust result of the model over a range of parameter variations. These results suggest that a model that combines satellite data on phytoplankton blooms with water column dispersed oil concentrations to estimate potential oil compound deposistion rates may be able to provide decision makers with guidance during an oil spill. However, additional, independent validation of the model is necessary before it can be adapted for use in an operational setting.

Violent expansion of a rising Taylor bubble

The gradual expansion of large bubbles rising in a liquid-filled tube can become violent in the last few seconds before reaching the tube top. This process is responsible for Strombolian volcanic eruptions and for accidents in deep-water oil drilling such as the 2010 Deepwater Horizon explosion.

Loss Causation and the Materialization of Risk Doctrine in Securities Fraud Class Actions

In the context of a claim for securities fraud under SEC Rule 10b-5, most federal circuit courts have ruled or recognized that loss causation can be proven by an event that demonstrates an earlier statement by a defendant company to be false. In other words, corrective disclosure need not take the form of speech. Rather, a statement can be shown to be false by the materialization of a risk that was concealed by the company, and investors can be compensated for any losses they suffer as a result. Although this materialization doctrine is well established, it is the thesis here that its ultimate effect is to over-compensate investors, thus encouraging excessive securities litigation and chilling voluntary disclosure. The point is graphically illustrated by the securities litigation that followed the Deepwater Horizon explosion and spill. There, plaintiffs argued that BP (the operator of the rig) had misrepresented its safety practices. Assuming the allegations to be true, the pre-event market price of BP stock would have been a bit lower, reflecting additional risk. If plaintiffs had paid that lower price, they would have had no claim as a result of the explosion and spill. So if plaintiffs recover an amount equal to pre-spill price inflation, they will be in exactly the same financial position as if they had bought knowing the truth. But most of the price decline following the event came from the prospect of cash outflows resulting from clean-up, repairs, fines, settlements, and possibly an increase in the cost of capital. To compensate buyers for these consequential losses is excessive. The risk of such losses is one that can be diversified away by investors. Moreover, if these consequential losses are actionable at all, they constitute a claim of mismanagement belonging to the company that should be pursued in a derivative action. To generalize: In cases in which loss causation can be shown only by materialization, the bulk of the claim is almost always more properly characterized as one on behalf of the company that should be resolved by a derivative action instead of by a class action on behalf of individual investors. Moreover, to recharacterize such claims as derivative carries significant collateral benefits: Because the company stands to recover (rather than to pay), derivative actions avoid the circularity problem endemic in class actions while providing a remedy that is perfectly tailored to the true (undiversifiable) loss suffered by investors. It is difficult to overstate the significance of this insight: It implies that much of securities litigation, as we know it must be recast as derivative rather than direct.

Conservation of resources and suicide proneness after oilrig disaster

The current study applied the Conservation of Resources (COR) disaster theory to explain suicide proneness after the Deepwater Horizon oilrig explosion. We had 213 residents in affected areas with complete measures of resource stability, distress, and coping 18 months after the disaster. Overall, 10% expressed clinically elevated suicide proneness. The COR model had excellent fit that accounted for 41% of inter-individual differences in suicide proneness. Aligned with theory, residents lacking resources who experienced distress and coped by avoidance were more suicide-prone. Fostering resource stability and constructive coping after catastrophe may help reduce suicide proneness and prevent suicide in disaster-impacted citizens.

Monique Verdin’s Louisiana Love: An Interview

“Monique Verdin’s Louisiana Love: An Interview” provides insights into the aesthetic choices and activism of Houma photographer and documentarian Monique Michelle Verdin. The interview begins with a discussion of Houma kinship relations with both land and water, considering the ecological devastation that corporate colonialism and climate change have wreaked on south Louisiana. This line of questioning leads to a discussion of her 2012 documentary, My Louisiana Love, of which she is both a producer and the central figure. She explains that she was trying to tell the story of her tribe, which inevitably led to documentation of how the gas and oil industry has ravaged south Louisiana’s wetlands through both pollution and pipeline construction. We also discuss how the personal losses in the film, resulting from Hurricanes Katrina and Rita (2005) and BP’s 2010 Deepwater Horizon oil rig explosion, make her own pain a focus that ultimately demonstrates intergenerational trauma. The interview then moves on to the ways in which her artistic work led to her activism, particularly by recording the damage sustained by the Gulf of Mexico and the coast due to the BP oil spill. The conversation describes how she has since created alliances with diverse Native peoples as the Gulf Coast representative for the Indigenous Environmental Network and through national and international activism, including at the 2015 United Nations Climate Change Conference in Paris (COP 21). The interview concludes with Verdin’s thoughts on environmental issues concerning south Louisiana today, including the proposed Bayou Bridge Pipeline and the impending resettlement of the Isle de Jean Charles tribe of Biloxi-Chitimacha-Choctaw due to rising sea levels.

Chemically dispersed oil is cytotoxic and genotoxic to sperm whale skin cells

Two major oil crises in United States history, the 1989 Exxon-Valdez oil spill in Alaska and the 2010 Deepwater Horizon Oil Rig explosion in the Gulf of Mexico, drew attention to the need for toxicological experiments on oil and chemically dispersed oil. We are still learning the effects these spills had on wildlife. However, little data is known about the toxicity of these substances in marine mammals. The objective of this study is to determine the toxicity of Alaskan oil, as well as chemically dispersed oil. Oil experiments were performed using the water accommodated fraction of Alaskan oil (WAF) and the chemically enhanced water accommodated fraction of Alaskan oil (CEWAF). The Alaskan WAF is not cytotoxic to sperm whale skin cells though it did induce chromosome damage; S9-mediated metabolism did not affect the cytotoxicity of WAF but did increase the levels of chromosome damage. Alaskan CEWAF is more cytotoxic and genotoxic than the WAF; S9 mediated metabolism increased both cytotoxicity and genotoxicity of CEWAF. Analysis of the PAH content of Alaskan WAF and CEWAF revealed a forty-fold increase in the total levels of PAHs in CEWAF compared to WAF. These findings show that chemically dispersed oil leads to higher levels of PAH exposure which are more toxic and likely to lead to longer and more persistent health effects.

The Gulf Coast Health Alliance: Health Risks Related to the Macondo Spill (GC-HARMS) Study: Self-Reported Health Effects.

The Deepwater Horizon (DWH) explosion in 2010 is the largest oil spill (Macondo) in U.S. history. We focused on gaining an understanding of the physical health and mental health effects attributable to the Macondo oil spill. This is a report of a cross-sectional cohort study (wave 1) to establish ‘baseline’ findings and meant to provide descriptive information to be used for a multi-wave, longitudinal study. Gulf Coast Health Alliance: health Risks related to the Macondo Spill (GC-HARMS) uses a Community-Based Participatory Research approach, thus including multi-disciplinary, multi-institutional academic partners and representatives of three communities impacted by the spill. Three research sites were selected for human sampling along the Gulf of Mexico coast including two from Mississippi and one from Louisiana, with Galveston, Texas, serving as a comparison site, given that it was not directly impacted by the spill. One hundred participants were selected from each community, representing adults, seniors and children, with approximately equal numbers of males and females in each group. Participants completed initial assessments including completion of a ‘baseline’ survey and, rigorous physical assessments. Results from wave 1 data collection reported herein reveal changes in self-reported physical health and mental health status following the oil spill, disparities in access to healthcare, and associations between mental health and emotional conditions related to displacement/unemployment. Few environmental health studies have been conducted in communities impacted by significant oil spills. Results imply potential prolonged effects on mental health and community vulnerability.

Modeling as a complementary tool to acoustic data for understanding the impact of environmental disasters on marine mammals

This study is focused on how environmental disasters, such as the Deepwater Horizon oil rig explosion in 2010, affect the dynamics of marine mammal populations, particularly sperm whales and beaked whales, in the Northern Gulf of Mexico. We briefly describe how modeling techniques are used to estimate densities of marine mammals using passive acoustic data. We then develop a matrix model to examine the possible long-term effects of a disaster. We consider cases in which the effects of a disturbance result in reductions in either survival (lethal impacts) or fecundity (sublethal impacts). This model, combined with demographic stochasticity, allows us to study the long-term recovery process following an environmental disaster. In particular, recovery probabilities and recovery times of the population are computed, and formulas are derived to compute the sensitivity of the recovery time to changes in properties of the population or the environmental disturbance. We then extend the modeling methodology to consider how marine mammals may be affected by the response of their prey population to a disturbance. Our analysis highlights the difficulty of projecting impacts and recovery in the absence of detailed demographic data, and the value of population models in exploring scenarios and identifying important processes and general relationships. [This research was made possible in part by a grant from The Gulf of Mexico Research Initiative.]

Analysis of lethal and sublethal impacts of environmental disasters on sperm whales using stochastic modeling

Mathematical models are essential for combining data from multiple sources to quantify population endpoints. This is especially true for species, such as marine mammals, for which data on vital rates are difficult to obtain. Since the effects of an environmental disaster are not fixed, we develop time-varying (nonautonomous) matrix population models that account for the eventual recovery of the environment to the pre-disaster state. We use these models to investigate how lethal and sublethal impacts (in the form of reductions in the survival and fecundity, respectively) affect the population’s recovery process. We explore two scenarios of the environmental recovery process and include the effect of demographic stochasticity. Our results provide insights into the relationship between the magnitude of the disaster, the duration of the disaster, and the probability that the population recovers to pre-disaster levels or a biologically relevant threshold level. To illustrate this modeling methodology, we provide an application to a sperm whale population. This application was motivated by the 2010 Deepwater Horizon oil rig explosion in the Gulf of Mexico that has impacted a wide variety of species populations including oysters, fish, corals, and whales.

The Gulf Long-Term Follow-Up Study (GuLF STUDY): Biospecimen collection at enrollment

ABSTRACTThe 2010 Deepwater Horizon (DWH) explosion in the Gulf of Mexico led to the largest ever marine oil spill by volume. The GuLF STUDY is investigating possible adverse human health effects associated with oil spill activities. One objective of the study was to utilize biological specimens from study participants to examine spill-related adverse health effects. This study describes the methods for collecting, processing, shipping, and storing specimens during the enrollment phase of the study. GuLF STUDY participants living in Gulf States (Alabama, Florida, Louisiana, Mississippi, and eastern Texas) were eligible to complete a home visit at enrollment, one to three years after the DWH explosion. During this visit, blood, urine, toenail and hair clippings, and house dust samples were collected. Specimens were shipped overnight to a central processing laboratory in containers with cold and ambient temperature compartments. Most blood and urine specimens were then aliquoted and stored in liquid nitrogen vapor or at -80°C, with some samples stored at -20°C. A total of 11,193 participants completed a home visit, and over 99% provided at least one biospecimen. Most participants provided blood (93%), urine (99%), and toenail clippings (89%), and 40% provided hair. Nearly all participants (95%) provided house-dust samples. Most samples were received by the laboratory one (58%) or two (25%) days after collection. These biospecimens enable investigation of a range of biomarkers of spill-related adverse health effects, and possibly some biomarkers of spill-related exposures. The biospecimen collection, handling, and storage protocols were designed to maximize current and future scientific value within logistical and budgetary constraints and might serve as a template for future studies conducted in similar time-critical and geographically dispersed settings.

CEO speeches and safety culture: British Petroleum before the Deepwater Horizon disaster

Abstract This paper explores the relationship between leadership language and the safety culture at British Petroleum [BP] prior to the April 20, 2010 Deepwater Horizon explosion in the Gulf of Mexico. The discursive construction of important aspects of safety culture in a large, risky, global company such as BP is a central feature of the CEO’s role. Using a social constructionist perspective, we conduct an interpretative close reading analysis of the speech of BP’s [then] CEO, Tony Hayward, at the Annual General Meeting of BP on April 15, 2010. We also analyse the transcripts of 18 other speeches Hayward delivered before the Deepwater Horizon explosion. We find that the language used contributed rhetorically to an ideology of economic efficiency and cost control, in a manner that was inconsistent with an enduring safety culture. We highlight important insights that close reading analysis of the narrative in CEO speeches can provide to help understand a corporation’s ambient safety culture.