Public health impacts of an imminent Red Sea oil spill

The ongoing conflict and blockade in Yemen have created a humanitarian crisis, further exacerbated by the derelict oil tanker Safer, abandoned off the coast since 2015. The Safer, a single-hulled vessel designated out-of-class since 2016, contains 1.1 million barrels of oil—more than four times the amount spilled by the Exxon Valdez. Its deteriorating condition significantly increases the likelihood of a catastrophic spill. This poses a major threat to the environment, economy, and public health of Yemen and the Red Sea region. Yemen’s vulnerability stems from its reliance on the Red Sea ports of Hudaydah and Salif for 68% of humanitarian aid, along with importing 90–97% of its fuel and 90% of its food. A spill would disrupt these critical import routes, impacting already strained resources for clean water, food, and healthcare. The potential for contaminated desalination plants further threatens clean water access across the region. The study investigates the imminent public health consequences of a major oil spill from the Safer, focusing on the disruption of essential services and the resulting health impacts, particularly in Yemen, a country already grappling with widespread food insecurity and a fragile healthcare system. The research aims to quantify the potential scale of the disaster to underscore the urgency of preventative measures.

Existing literature highlights the ecological and economic consequences of major oil spills. Studies like Kleinhaus et al. (2020) have documented the danger the Safer poses to the Red Sea's ecosystem. However, a comprehensive characterization of the immediate public health impacts remains absent. The study builds upon previous research on the impacts of fuel shortages and port closures in Yemen, showing the severe consequences on access to clean water, healthcare, and food security (Alles, 2017; Fink, 2017; Sowers & Weinthal, 2021). Research on the health effects of oil spills, including cardiovascular and respiratory issues from air pollution (Goldstein, Osofsky & Lichtveld, 2011; Alexander et al., 2018; Kloog et al., 2013; Wei et al., 2019; Burnett et al., 1999), provides a basis for estimating potential health burdens. The study leverages this existing knowledge to model the specific public health ramifications of a Safer oil spill in the context of Yemen's ongoing humanitarian crisis.

The study utilizes a combination of modeling techniques to simulate oil spill trajectories and assess public health impacts. Oil spill trajectories were modeled stochastically using the NOAA's General NOAA Oil Modeling Environment (GNOME) model. This model incorporates historical weather data (wind and currents from ERA5 and HYCOM datasets) and the properties of the Marib Light crude oil carried by the Safer. 1,000 Monte Carlo simulations were conducted for both summer and winter conditions, to account for the inherent uncertainty in weather patterns. The model outputs average surface oil concentrations at various time points, indicating potential impact on ports and desalination plants. Oil fate was assessed using NOAA's Automated Data Inquiry for Oil Spills tool, considering both scenarios with and without optimistic clean-up interventions (skimming, in situ burns, dispersants). The air pollution resulting from the spill was modeled using NOAA's HYSPLIT model. This model simulates the atmospheric transport and dispersion of pollutants from both evaporation and combustion. Simulations considered variations in spill duration (fast- and slow-release) and season. The model outputs pollutant concentrations (PM2.5), which were then used in conjunction with existing epidemiological data (Burnett et al., 1999; Kloog et al., 2013; Wei et al., 2019) to estimate the increased risk of cardiovascular and respiratory hospitalizations. Data on fuel imports, food aid, and desalination plant capacities were compiled from various sources (UN OCHA, WFP, UNVIM) to assess supply disruptions. Uncertainty analysis was incorporated throughout, with 95% uncertainty intervals provided for key estimates to reflect the inherent uncertainties of modeling and the limitations of available data.

The modeling indicates that most simulated oil spills would move towards Yemen's northwest coast, reaching the key ports of Hudaydah and Salif within 6-10 days. Seasonal variations in spill trajectory were observed, with summer spills tending to move southeast and winter spills moving north. Approximately 51% of the oil is estimated to evaporate within 24 hours, with clean-up interventions having a negligible impact in the initial six days. Port closures are highly likely, disrupting the delivery of approximately 200,000 metric tons of fuel per month of closure (equivalent to 38% of Yemen's needs). This disruption would likely lead to fuel price spikes, similar to those observed during previous port closures. The spill is also projected to disrupt the daily clean water supply for 1.0-1.9 million people through contamination of desalination plants. Food aid would be disrupted for an estimated 5.7-8.4 million people dependent on ports, and 93-100% of Yemen's Red Sea fisheries would be threatened. The air pollution from the spill is predicted to increase the average risk of cardiovascular and respiratory hospitalizations by 5.8% to 42%, depending on the spill scenario (leak vs. combustion, fast- vs. slow-release, season). Clean-up workers would face a significantly higher risk of hospitalization due to direct exposure.

The findings demonstrate the potential for a catastrophic public health crisis resulting from a Safer oil spill. The disruption of essential services (fuel, water, food) would exacerbate existing vulnerabilities in Yemen, potentially triggering outbreaks of waterborne diseases, increased malnutrition, and further strain on the already overburdened healthcare system. The projected increase in respiratory and cardiovascular hospitalizations would place an additional burden on the healthcare infrastructure, further hindering the ability to respond to the disaster. The study's findings underscore the interconnectedness of environmental disasters, economic instability, and public health. The scale of potential damage highlights the need for international cooperation and immediate action to prevent this impending catastrophe. The results are robust despite acknowledged uncertainties in model parameters and data availability. The consistent prediction of severe public health impacts across multiple scenarios reinforces the urgency of intervention.

This study provides compelling evidence of the catastrophic public health consequences of an imminent oil spill from the Safer tanker. The projected disruptions to fuel, food, and water supplies, coupled with the increased risk of respiratory and cardiovascular illness, underscore the urgency of preventing this disaster. The findings strongly advocate for immediate international action to offload the oil and mitigate the potential for widespread suffering. Future research should investigate the long-term health and ecological impacts of such a spill, as well as the effectiveness of different mitigation and response strategies.

The study acknowledges several limitations. The oil spill model relies on historical weather data, which may not fully capture the variability of extreme weather events. Data quality varied across different datasets, potentially introducing measurement error. The analysis focuses on immediate public health impacts; long-term consequences and global trade disruptions require further investigation. The model assumes a full spill scenario; partial spills could have different impacts. The exact timing of port closures and clean-up efforts cannot be precisely predicted, influencing the duration of supply disruptions. The air pollution modeling relies on assumptions about the conversion of oil to particulate matter and epidemiological risk estimates that might not perfectly reflect the Yemeni population.