Toxicology

Top Gun Toxicity: Military-Grade Hydrocarbon Exposure Management in the ED

Introduction
November 2021 was a difficult month for members of the U.S. Armed Forces and Hawaiians on Oahu. The Red Hill bulk oil storage facility, in use since the 1940s, was found to have leaked a copious amount of aviation and maritime fuel into local aquifers, which serve as the exclusive supply of potable water to Hawaii.1,2

Although Red Hill had leaked previously in 2014, the November 2021 leak marked the first time that a fuel leakage led to unsafe drinking water. This leak was first noted by those in military residences who observed that the water emanating from the tap had the strong odor of petroleum.

Since the 2021 leak, Red Hill has been shut down per directive from Secretary of Defense Lloyd Austin III.1,2 The ramifications of military fuel exposure extend beyond this environmental disaster to acute exposures/ingestions and chronic toxicity. With more than 450 military bases in the United States, many of which utilize the same fuel as Red Hill called JP-8, the emergency physician should be familiar with the presentation and management of military-grade hydrocarbon toxicity.

Military Fuel 101: The Basics
JP-8, which stands for Jet Propellent 8, is a mixture of hundreds of hydrocarbons used as fuel in military aircraft engines and less commonly marine engines. Many of the same hydrocarbons are also present in gasoline and Jet-A, the civilian aircraft fuel.

JP8 Seahawk.jpeg
A U.S. Navy MH-60S Seahawk helicopter performing training operations off the coast of Virginia. Photo courtesy of Dr. E. Mason Jackson.

The largest difference between military and civilian fuel is the presence of several additives including deicers and antioxidants. JP-8 is a distillate of kerosene and is composed of aromatic (e.g., benzene) branched and straight chain alkanes (e.g., decane), and naphthalenes, among others. U.S. Navy and Coast Guard vessels utilize gas turbines and can use JP-8 for power if their usual diesel-based fuel, F76, is not available.3,4 For logistical purposes, most reservoirs of fuel are housed in bulk at various facilities to allow for controlled distribution, safeguarding, and ease of use.

Case
Three national guard soldiers in their early 20s with no relevant past medical history presented to a tertiary care level 1 trauma center after a large volume JP-8 exposure occurred while they were working on the flight line at a local airbase. They stated that they were defueling an aircraft when the pressurized hose exploded, spraying fuel over their face, upper extremities, chest, and abdomen. They all endorsed aspirating and/or swallowing some of the fuel by accident and denied any fire or burns. They also reported some ocular burning, nausea, and abdominal discomfort.

Stabilization and Initial Management
As with most occupational exposures, the initial step in management is decontamination of the patient. Copious irrigation of the eyes and skin exposed to the fuel should be performed and soap should be used, if possible, for dermal exposures. This should be done ideally by EMS prior to transport or done on arrival to the ED. Exposed or contaminated clothing should be removed. Rigorous and recurrent assessments of the patient’s airway, breathing, and circulatory parameters should be initiated and continuously monitored, as hydrocarbon exposure manifests through a wide spectrum of toxicity.

Acute Toxicity and Management
Acute toxicity, which is most relevant to the emergency physician, has several facets that deserve individual recognition.

1) Pulmonary. The pulmonary effects of hydrocarbon exposure represent one of the most life-threatening components of JP-8 toxicity and are mediated by the physical properties of volatility, surface tension, and lipophilicity. High volatility of JP-8 and other combustion fuels cause aspirated liquid to transform to a gas, leading to displacement of oxygen and resultant hypoxia with ventilation-perfusion mismatch. Elevated surface tension causes “creep” of fluid along a solid surface and increases the risk of aspiration with oral exposures. In addition, hydrocarbons disrupt alveolar surfactant, leading to worsening pulmonary mechanics (e.g., decreased compliance) and pneumonitis with interstitial inflammation, alveolar edema/hemorrhage, necrosis, and inflammatory exudates.5 Intubation and lung protective ventilation should be performed for refractory hypoxia or mechanical respiratory failure. Development of lipoid pneumonia can also be seen for large or severe pulmonary exposures.3,5

2) Cardiovascular. All hydrocarbons, JP-8 included, sensitize the myocardium through unknown mechanisms; however, some substances like halothane and chloroform stabilize ion channels blocking myocardial depolarization.5 It is theorized that slowed gap junction conduction also contributes to profound myocardial dysfunction, which is manifest though recalcitrant ventricular dysrhythmias often precipitated by a sudden catecholamine surge. This sensitization is possible through any exposure means, including dermal, pulmonary, and gastrointestinal. Bicarbonate should be considered in those patients with wide complex tachycardias as a result of the exposure; however, as described, the pathophysiology of cardiotoxicity is multifactorial and may require ECMO or other invasive measures aside from high-quality advanced cardiac life support.5

3) Gastrointestinal. When ingested, hydrocarbons are primarily gastric irritants, frequently causing spontaneous vomiting and GI discomfort. There have been case reports of hemorrhagic gastritis; however, this is more common in large volume ingestions and is more classically seen with isopropyl alcohol ingestion.3,5 Symptomatic care is indicated for these patients and includes viscous lidocaine, antiemetics, and analgesia if other contraindications do not exist.

4) Dermal. Chronic or prolonged skin exposure to JP-8 and other hydrocarbons leads to partial or full thickness skin necrosis via a defatting process. These substances also serve as immune sensitizing agents, and patients can present with allergic dermatitis similar to poison ivy or other delayed type IV hypersensitivities. The dose of hydrocarbon absorbed is proportional to the area of skin exposed and the duration of exposure.5 Similarly, although less common, ocular manifestations include hyperemic conjunctiva and a burning sensation.3 Decontamination with soap and water for skin contact and irrigation for ocular exposures is effective in decreasing ongoing toxicity to the patient and ensuring the safety of the healthcare team.

Tip: Although cardiovascular and pulmonary toxicity are most life threatening with JP-8 exposure, most individuals exposed to JP-8 or other hydrocarbons orally likely will present with less severe symptoms such as gastrointestinal distress, nausea, and vomiting.

Chronic Toxicity
Chronic exposure to JP-8 has shown to be directly cytotoxic with cells altering gene expression causing untimely cell death with concomitant dysregulation of DNA maintenance and metabolism controlling proteins. Workers exposed to high quantities of JP-8 were at high risk for development of rare malignancies and early death.6 Some limited evidence also supports the development of neurotoxicity with adverse effects on mood, cognition, balance, and hand grip.Although the diagnosis of chronic JP-8 toxicity likely exists outside of the emergency department, the emergency physician should be able to recognize a symptomatic patient whose history is consistent with chronic military fuel or other hydrocarbon exposure. These individuals should be referred to primary care or to an occupational toxicologist.

Environmental Effects
Volatile organic compounds such as those in JP-8 have far-reaching epidemiological consequences, as stated above. The Red Hill incident affected more than 90,000 service members and families, took approximately three months to restore potable water, and created a two-year continual water-testing requirement in addition to the labor-intensive Red Hill water well clean-up.1 Runoff not only creates a health hazard due to exposure, but with a flashpoint of 100.4F poses a very real threat of volatile explosion should vapors accumulate.8 It is important to consider that clean-up operations after a spill or explosion place relief workers at health risk due to inherent exposures, as was seen following the British Petroleum Deepwater Horizon oil rig explosion in 2010. Additionally, chemical dispersants used for clean-up operations have their own potential effects, many of which have little research.9

Case Conclusion and Learning Points
Fortunately, all three National Guard soldiers did not have any signs of symptoms of acute JP-8 toxicity. After an appropriate observation period and negative chest X-rays, all were discharged back to base.

Occupational exposures are a constant, albeit infrequent, threat that the emergency physician must be prepared to recognize and treat. Exposure to JP-8 and other hydrocarbons pose the greatest danger with aspiration, but other considerations include prolonged skin contact, ingestion, and possible cardiotoxicity. Significant pulmonary pathology includes alveolar collapse, decreased compliance, impaired gas exchange causing ventilation-perfusion mismatch, respiratory failure, and rarely a lipoid pneumonia stemming from fibrous tissue encapsulating damaged alveoli. Respiratory symptoms must be monitored, and if they arise, a chest radiograph with six-hour observation time should follow.10 Cardiac pathology and CNS effects are more likely seen with intentional inhalation or in patients with significant time exposure while in confined spaces. Electrocardiogram will aid in concern for dysrhythmias. Skin must be thoroughly decontaminated as soon as possible following exposure and all clothing removed. Gastrointestinal effects typically require only supportive care. Referencing chemical safety data sheets and contacting a poison control center are critical.

Disclaimer: The views expressed in this article do not necessarily represent the position or endorsement of the U.S. government, Department of Defense (DoD), or entities contained within the DoD.


References

  1. Drinking Water Emergency at Joint Base Pearl Harbor-Hickam, Honolulu, Hawaii. EPA. Published June 5, 2022. Accessed July 8, 2022.
  2. Ives M. Pentagon Will Close Hawaii Fuel Depot That Leaked Petroleum. New York Times. March 8, 2022;20.
  3. Rishler J, Faroon O, Llados F, Ingerman L, Citra M. Toxicologic Profiles for JP-5, JP-8, and JET A Fuels. Atlanta, GA: U.S. Department of Health and Human Services, Division of Toxicology and Human Health Sciences. 2016.
  4. F76 Military Diesel. Citgo Safety Data Sheets. Published March 22, 2018. Accessed July 5, 2022.
  5. Hoffman RS, Howland M, Lewin NA, Nelson LS, Goldfrank LR, eds. Goldfranks Toxicologic Emergencies, 10e. McGraw-Hill. 2015.
  6. National Research Council (U.S.) Subcommittee on Jet-Propulsion Fuel 8. Toxicologic Assessment of Jet-Propulsion Fuel 8. Effects of Jet-Propulsion Fuel 8 on the Nervous System. Washington (DC): National Academies Press (US). 2003;5.
  7. Bowling F, et al. Report on the Molecular Investigations into the Jet Fuel and Solvent Exposure in the DeSeal/ReSeal Programme Conducted at the Mater Research Institute (UQ), Brisbane. Brisbane, Queensland: Mater Research Institute; 2014.
  8. Jet Fuel JP-8. Hess Material Safety Data Sheets. Published August 30, 2012. Accessed July 5, 2022.
  9. Swienton RE, Subbarao I. Basic Disaster Life Support: Course Manual 3.0. National Disaster Life Support Foundation; 2012.
  10. Walls R, Hockberger R, Gausche-Hill M, eds. Rosen’s Emergency Medicine Concepts and Clinical Practice. 9th ed. Philadelphia, PA: Elsevier; 2018.

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