Hazards of Hawai‘i Volcanoes National Park

Introduction

For the wilderness enthusiast, Hawai‘i is renowned as a safe tropical destination free from snakes, diseases of the developing world, and dangerous animals. One of the most popular destinations is Hawai‘i Volcanoes National Park. With over a million visitors per year, the park is one of the top fifteen visited national parks in the United States.¹ It possesses the only active volcanoes, with unique hazards such as the terrain of established lava flows, unstable lava deltas, lava, and volcanic gases. A visitor can sustain trauma, altitude related illness, burns, hyper and hypothermia, and exacerbation of existing lung conditions.

Relevance to Hawai‘i and Asia-Pacific

Advancing lava has destroyed multiple communities on the island of Hawai‘i (Big Island) since Kilauea's latest eruption began in 1983.² This has substantially altered the terrain, destroying infrastructure, and making it difficult to traverse by vehicle or foot.² Vog, a mixture of sulfur dioxide (SO2) and other gases emitted from a volcano reacting with oxygen in sunlight, exacerbates respiratory and ocular conditions in susceptible individuals. Concentrated levels of SO2 above World Health Organization (WHO) recommended exposure levels exist frequently on Hawai‘i island communities southwest of Kilauea, downwind of the usual northeasterly trade winds.³

Clinical Relevance

Kilauea, the more active of the two active shield volcanoes on Hawai‘i Island, has historically produced an average of over 100 tons per day of sulfur dioxide, the most abundant gaseous emission.⁵ In some of the more active years since 1983, rates have exceeded 1,000 tons per day.³ In addition to sulfur dioxide, considerable quantities of hydrogen sulfide, carbon dioxide, carbon monoxide, hydrochloric acid, and particulate matter are produced.⁶ These gases can produce acute effects on visitors with chronic respiratory and cardiac disease.

Traversing the terrain of the lava fields causes hundreds of mechanical injuries each year, including lacerations, abrasions, fractures, sprains, and strains.⁴ Additionally, dozens of thermal burns have been recorded over the last twenty years, including several fatalities.⁴

Sulfur dioxide is a colorless gas; however it is frequently mixed with other gases and particulate matter. It has a strong odor which most people can detect at 0.3 to 1 ppm, and is irritating to the respiratory tract.⁷ OSHA limits on sulfur dioxide exposure are an eight hour total weighted average of 2 ppm and a short term (15 minutes) exposure limit of 5 ppm.⁷ Asthmatics can experience increased airway resistance with sulfur dioxide concentrations of less than 0.1 ppm when exercising. Healthy adults experience increased airway resistance at 5ppm, sneezing and coughing at 10 ppm, and bronchospasm at 20 ppm.⁸ Respiratory protection is required for exposures at or above 20 ppm.⁷ Sulfur dioxide exposure in the National Park varies widely depending on location and wind direction. With normal northeasterly trade winds the most highly trafficked areas such as the Visitor's Center and Jagger Museum are likely to experience less than one ppm to zero sulfur dioxide exposure.⁹ Close to vent sites and several kilometers downwind, visitors can experience levels over 1 ppm and even over 100 ppm in very close proximity.⁹ Measurements up to 75 ppm have been recorded at lava coastal entry sites, locations which are particularly sought by visitors.⁹

Exposure to sulfur dioxide in large quantities has been documented to produce reactive airways dysfunction syndrome (RADS).¹⁰ RADS falls within the same spectrum of disease as irritant induced asthma, and can present as acute asthma in individuals with no prior history after just a single high dose exposure. RADS can lead to long-term asthma-like symptoms that persist for years. It is not well characterized histologically, and is not known to be immune mediated.¹⁰ In several studies of RADS, a majority of patients experienced symptoms following methacholine challenge, and spirometry continued to be abnormal over five years later. While most studies show a mild inflammatory response with sparse lymphocytes and granulocytes, there is an absence of eosinophilia, smooth muscle hyperplasia or mucus gland hypertrophy that are characteristic of asthma.¹⁰

Hydrogen sulfide is also a colorless gas with a distinctive rotten egg odor that is emitted in sizeable quantities from Kilauea.⁹ From May to September 1993, the maximum recorded measurement of H₂S was 4.23 ppm at Sulphur Banks, but from 1987–1990 measurements only rarely exceeded the Hawai‘i State Department of Health air quality limit of 0.025 ppm at the park monitoring site.⁹ OSHA total weighted average exposure limit for H₂S is 10 ppm, with a short term exposure limit 15 ppm.⁹ At concentrations above 20 ppm, exposure can elicit headaches, dizziness, nausea and eye irritation. Respiratory effects include bronchitis, rhinitis, and pulmonary edema.¹¹ Studies indicate that hydrogen sulfide inhibits cytochrome oxidase (aa3) resulting in disruption of the electron transport chain and inhibition of oxidative metabolism in the mitochondria.¹² More recent experiments have determined that greater toxicity may result from the production of reactive oxygen species and depletion of glutathione.¹³ No recorded deaths from H₂S exposure have occurred in Hawai‘i, although numerous deaths have occurred in areas of volcanic activity in Japan and New Zealand.⁶ Hydrogen sulfide toxicity is primarily a concern of industrial exposure.¹⁴ This is a very small primary volcanic HC1 gas emission. It is produced in greater quantities when lava exceeding 1,100 degrees C interacts with chlorides in seawater, and is a component of the superheated steam plumes.⁹ While 1994 USGS ambient air measurements recorded only one ppm of HCl at a coastal entry point for lava within the park, this was skewed by the fact that the measuring device only recorded gas, not aerosol vapor. The pH of rain water sampled at the same site supports the theory that the HCl measured levels are not an accurate indication of total HCl concentration.⁹ OSHA has a permissible exposure limit of 5 ppm established. Exposures to 35 ppm causes throat irritation and, with higher concentrations over time, can result in swelling and spasm of the throat and bronchospasm. The resulting endothelial damage at high exposure levels may lead to pulmonary edema, progression to acute respiratory distress syndrome (ARDS), and may induce RADS.¹⁵

While exposure to gases poses a risk and has produced injuries and fatalities, most injuries and fatalities are caused by motor vehicles on the roadways or air travel accidents.⁴ These caused 178 of 262 park fatalities during 1993 to 2002.⁴ Other causes of death from this period during a study of park hazards indicated that thermal burns, heat stroke, cardiac arrest, respiratory distress, and mechanical injury rounded out the remainder.⁴

Example Cases

From 1983 to 2003, five deaths of tourists were directly due to SO₂ exposure, with few details available. One person had a history of asthma. The other four deaths occurred when these individuals ignored warning signs for off-limits areas marked during periods of elevated volcanic activity.⁶ A closer study from 1993 to 2002 indicated that there were 28 asthma and respiratory distress related deaths, but these were not attributed to a single gas at the eruption site of Kilauea.⁴

On November 5, 2000, a woman, age 41, of Volcano, Hawai‘i, and a man, 42, of Washington, DC, were found dead near the lava flow front entry into the ocean.¹⁶ They were found with severe burns, cuts and abrasion to their heads, hands, and knees.¹⁷ According to the medical examiner, “the two died as a result of pulmonary edema caused by inhalation of steam sustained when exposed to a steam plume.”¹⁷ While the investigation did not elaborate further regarding the specific etiology of the pulmonary edema, hydrochloric acid and superheated water steam itself are possible causes of such injuries. Of note, the autopsy summary reported advanced decomposition of the exposed skin due to acid rain.¹⁸

While relatively uncommon, thermal burns have caused high profile injuries and fatalities in the park.⁴ In October 2002, a cruise ship passenger, age 45, was found dead just north of the ranger station at the end of Chain of Craters Road.¹⁹ There were no obvious injuries, foul play was ruled out, and she was not found in immediate proximity to active lava flows. However, it was later reported that she was found twenty feet into a cooling lava flow.²⁰ The official autopsy report declared that she died of natural causes due to exposure.¹⁶ A lawsuit brought against a tour company that transported her to the park mentioned burns to her feet and other skin surfaces.²⁰ A visitor from Japan died in the late 1980s when he fell on uneven lava while hiking at night from the flow front to his car parked near Kalapana.¹⁹ In March 2003, a man suffered a mix of first, second, and third degree burns over eight percent of his body when he fell into an active flow.¹⁶

In April 1993 a local native of the island of Hawai‘i, a Kona photographer, died at Kilauea's Eruption Site when a lava bench which appeared to be solid collapsed.²¹ He was attempting to photograph the entry site of lava into the ocean. He and several other onlookers had crossed a rope barrier set up by park rangers. When the bench collapsed, the others were able to scramble to safety, but Nagar was swept into the sea. Five years later, in April 1998, a hiker was declared lost at sea after an extensive search when he slid off a coastal cinder cone at the ocean edge. This occurred at approximately 1 a.m. when the group with whom he was hiking crossed a warning barrier.²²

Treatment in Resource-Constrained Environments

Persons entering the backcountry remote areas should ensure avoidance of areas with significant concentrations of toxic gases by using basic information provided by the National Park Service. This is particularly important for individuals with pre-existing asthma, COPD, or interstitial lung disease. Patients with pre-existing conditions should carry an adequate supply of their control medications and avoid high-risk areas. Guides should consider carrying spare inhalers with a quick-acting beta-agonist and possibly an inhaled corticosteroid. Mechanical injury or dehydration are the most likely situations requiring medical care in the park. Individuals should be advised to prepare their skin for sun exposure, travel with water, wear proper footwear, and maintain an ability to contact help should such an injury prevent self-evacuation.⁴ Additionally, visitors into the backcountry should register with the park service before venturing into less trafficked areas of the park.⁴

The levels of gas exposure frequently experienced by hikers and outdoor enthusiasts on Kilauea are not likely to harm an able-bodied individual. It is unlikely the victim or first responder will be able to identify the exact gas that is the offending agent in the field without specialized equipment. Therefore, treatment should focus on maintaining the airway and delivering oxygen. The treatment for exposure to sulfur dioxide is similar to an acute asthma attack.⁷ Manifestations can include coughing, bronchospasm, upper airway edema, acute lung injury, and death at exposures above 20ppm.⁷ First line treatment includes immediate removal from the exposure, use of an inhaled beta-2 agonist and oxygen support. An emergency room visit is indicated for observation or further treatment.⁸ There is minimal risk of secondary exposure to first responders once the patient is out of the contaminated environment.⁸

For HCl exposure, secondary contamination of the rescuer is not a concern if the victim is dry; moist contaminate could expose the rescuer to vapor.¹⁵ Skin or eye irritation should be decontaminated with removal of clothing and thorough washing with soap and water.¹⁵

Treatment in Non-Austere Environments

There is no direct antidote for sulfur dioxide toxicity. Treatment consists of support of respiratory and cardiovascular functions. Treat bronchospasm with immediate acting aerosolized bronchodilators such as aerosolized beta-2-agonists.⁷ Additional treatment includes long acting aerosolized beta-2-agonists, IV and inhaled corticosteroids, oxygen and even intubation as the clinical picture dictates. The use of aerosolized 2% sodium bicarbonate solution has been documented as a successful treatment and is a consideration in more concentrated exposures.²³ In theory, this helps neutralize and prevent the formation of sulfurous acid and breakdown products which are involved in bronchoconstriction.²³

For eye irritation due to sulfur dioxide exposure, remove any contact lenses and flush the eyes for at least fifteen minutes. For skin exposure, flush skin with water for fifteen minutes, removing from contact any contaminated clothing and shoes. The clothing and shoes may be washed thoroughly and reused.⁷ Patients without pulmonary complaints in a 6- to 8-hour observation period are not likely to develop complications. They may be released and advised to rest and to seek medical care promptly if symptoms develop.⁷ For symptomatic patients, the injury may evolve over the course of 18 to 24 hours depending on the level of exposure and co-morbidities of the patient.⁷

Treatment for acute hydrogen sulfide toxicity begins with supportive care: removal from the offending site, administration of oxygen and suctioning of secretions.¹⁴ Antidotes to consider if hypoxia is not readily corrected with oxygen include those which will induce methemoglobinemia such as high dose inhaled amyl nitrate and IV sodium nitrate.¹⁴ Inhaled amyl nitrite should be avoided if the individual is hypotensive, because a primary mechanism of action is cardiac and peripheral smooth muscle relaxation. Ten mL of 3% IV sodium nitrite over two to four minutes, and IV pyridoxine are more likely to be more effective in inducing the desired methemoglobin state.¹² The methemoglobin production will scavenge the offending sulfide species, forming a transient sulfmethemoglobin species with a half life of two hours at 24 degrees Celsius which will further decay into oxyhemoglobin and an oxidized form of sulfur.¹² Other treatments to consider include hyperbaric oxygen and therapeutic red cell exchange.¹⁴

The mechanism of hydrochloric acid toxicity is due to corrosive effects and the formation of free radicals causing parenchymal damage to the lung.²⁴ The care is supportive. Bronchodilators may be required to counteract bronchospasm.²⁴ Non-invasive ventilation devices may be required to maintain oxygen saturation and intubation may be required. For pulmonary edema, in addition to oxygen support, loop diuretics are the drug of choice, with furosemide having the added benefit of venodilation effects, reducing preload. For furosemide, start with a dose of 0.5mg/kg, up to 1mg/kg for renal insufficiency or chronic diuretic use.²⁵ Other agents that reduce preload, such as nitrates, are also effective as long as hypotension is not present or induced. Morphine also induces venodilation and relieves dyspnea and anxiety while reducing catecholamine effects that increase afterload.²⁵ ARDS is a documented consequence of HCl toxicity that requires extensive supportive care time and resources.

Treat carbon dioxide and monoxide poisoning with supplemental oxygen. The half life of COHb at room air is five hours.²⁶ Normal COHb levels in the blood are 1–3%, and can be increased in smokers up to 5–10%. Levels measured above this on an arterial blood gas require supplemental 100% oxygen therapy, which will reduce the half life of COHb to 74 minutes.²⁶ According to Center for Disease Control (CDC) guidelines, COHb levels above 25% or the presence of cardiac or neurological impairment are indications for hyperbaric O2 therapy, which is the gold standard for care and reduces COHb half life to 25 minutes.²⁶ A literature search did not find the levels of COHb or subgroups of victims that would most likely benefit from hyperbaric oxygen therapy.²⁷

Conclusion

While volcanic gas and lava flow injuries are important, the vast majority of park injuries are due to motor vehicle accidents and man-made hazards. Most of the over one million tourists to Hawai‘i Volcanoes National Park report no incidents at all. If the visitor is properly equipped, conditioned, realistic about their health, and willing to follow the signs, they will likely avoid becoming a story in a newspaper. In a 2004 survey of 800 hikers leaving the lava fields, which often involves a 10-plus kilometer hike to view active lava, 93% of respondents admitted hiking beyond warning signs posted 500 meters from the eruption site where the lava meets the ocean. Over half were ill prepared, defined as lacking flashlights, sufficient water, first aid kits, and sunscreen.¹⁸ Many had pre-existing health issues, including heart problems and asthma.¹⁸

It is prudent to remember to use vehicle safety measures, a hydration plan, protection from the sun, and proper footwear when traversing terrain by foot. Individuals with pre-existing respiratory and cardiac conditions should have a supply of medication, minimize physical stress, and consult the air quality guide for the park at http://www.hawaiiso2network.com/ managed by the US Geological Survey. Finally, obey all signs placed by park personnel that warn visitors of hazards such as unstable terrain and high levels of toxic gases.

Disclosure

The author reported no conflicts of interest.

Disclaimer

The views expressed in this publication are those of the author and do not reflect the official policy or position of the Department of the Army, Department of Defense or the US Government.