introduction to the epidemiological aspects of explosive

CHAPTER 1

Introduction to the Epidemiological Aspects of Explosive VolcanismROBERT S. BERNSTEIN, MD, PHD, PETER J. BAXTER, MD, AND A. SONIA BUIST, MD

BackgroundAlthough mankind has always been exposed to natural

hazards such as hurricanes, tornadoes, volcanic eruptions,and earthquakes, data on their occurrence, nature, andimpact have only recently been gathered by valid and reliablemethods. 1'2 Throughout historic times, natural disasters havebeen responsible for millions of deaths, countless injuries andillnesses, and extensive but poorly characterized psychoso-cial and economic effects. Our vulnerability to severe,unpreventable natural hazards has stemmed in large partfrom our propensity to underestimate their seriousness or todeny the risk.' However, a complicating feature of humanvulnerability to these destructive events has been the agri-cultural, economic, or aesthetic attractiveness of geographicareas in which severe weather, volcanic eruptions, andearthquakes occur relatively often."

To prevent disaster-related injuries, illnesses, anddeaths, natural hazard predictions must provide warning ofthe probable nature, location, time ofonset, and severity withsufficient lead time after recognition of precursor events. Inrecent years, the ability to predict and provide adequatewarning about severe weather has improved considerably(particularly for hurricanes) due to the widespread applica-tion of radar and satellite monitoring in the more developedcountries. Similarly, in the last few decades, there have beenmajor improvements in the ability to detect geochemical andseismic precursors of volcanic eruptions and earthquakes;however, the necessary human and technical resources to doso are not widely available; moreover, we cannot be certainhow far and how fast an abnormal situation will escalate.'

The experience at Mount St. Helens demonstrated that,even with the most modern equipment, a detailed historicaland geophysical record of previous activity, and a group ofthe best-trained professionals on-site during two months ofpremonitory activity, volcanologic monitoring methods wereoflimited reliability and precision in the prediction ofthe timeofonset and nature of explosive activity.5'6 Subsequent to theMay 18, 1980 earthquake and blast, volcanologists haveprovided reasonably reliable warning of forthcoming minoreruptions by monitoring such phenomena as precursoryseismicity, deformation of the crater floor and the lava dome,and, to a lesser extent, gas emissions.7 The lead times forthese hazard predictions have been increasing from tens ofminutes in 1980 to between three days and three weeks atpresent.7 It remains to be seen whether the increasingreliability of predictions with adequate lead times will beapplicable to major eruptions at Mount St. Helens and otherless intensively monitored volcanoes.

During recent historic times, the collection and evalua-tion of natural hazards data have been inadequate for theneeds of those engaged in evaluation of pre-disaster planningand preparedness and post-disaster response."2 There havebeen few systematic epidemiologic studies of natural disas-ters and limited opportunities for multidisciplinary research

NOTE: Author affiliations and addresses are listed on p vi.

by a team of geological scientists and epidemiologists trainedin environmental health sciences.>'0

Such collaborative efforts could be very important in thedesign of "primary" and "secondary" preventive measuresfor natural hazards and in identifying barriers to the imple-mentation and operational effectiveness of such measures.Primary preventive measures are those which interrupt thetransmission or causation of illness and injury by controllingor eliminating exposures to the hazardous agent(s). A well-planned, timely, and safely executed evacuation to healthfultemporary residential quarters is an example of "primary"prevention of morbidity and mortality due to explosivevolcanism. Secondary preventive measures are those whichreduce the severity, duration, and spread or extent ofillnesses and injuries which have already occurred by the useof appropriate search and rescue, clinical treatment, envi-ronmental management, and epidemiological practices. "1There are inadequate data on the relative costs and benefitsof partitioning different amounts of limited resources to"prinmary" versus "secondary" measures for preventingexcessive morbidity and mortality in natural disasters. Thecosts to society and affected individuals may be quite highwhen large populations are evacuated to temporary quartersfor an extended period of time, especially if disaster expertshave "cried wolf" on the basis of the best available data andno disaster occurs." 7 The occurrence of large-scale disastersprovides important, but rapidly perishable opportunities forapplied research which may be relevant to pre-disasterplanning, disaster responsiveness, and to other matters ofpublic health concern (e.g., the comparative toxicology andepidemiology of exposures to air pollutants released fromexplosive or effusive volcanism, from the combustion offossil fuels, and from fires in public places)."'6 The difficultyin rapidly mobilizing sufficient funds to conduct well-de-signed (peer-reviewed) cross-sectional and longitudinal fieldstudies, with necessary laboratory investigations, is amongthe most critical barriers to obtaining such data.

When a large-scale natural disaster occurs, investigatorsrarely have the opportunity or resources to investigate theinfluences ofpreventive measures and risk factors for indirectand delayed adverse effects. Evaluation of the effectivenessof primary and secondary preventive measures for naturaldisasters requires specific data concerning the:

* nature and extent of primary preventive measures,including pre-disaster planning and preparedness, predic-tive capabilities, warning systems, and evacuation efforts;

* universe of potentially hazardous "agents" associatedwith severe weather and seismic hazards;

* number and vulnerability of people at risk;* influence of environmental, social, and political fac-

tors;* factors associated with survival as well as with injury,

illness, or death among the population at risk for exposure;* etiology and clinical characterization of adverse ef-

fects on health, safety, and well-being;* performance as well as design characteristics of disas-

ter responses (triage, transportation, and treatment ofmass

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BERNSTEIN, ET AL.

casualties; search and rescue operations; etc.) and othersecondary preventive measures (e.g., social, mentalhealth, and economic assistance programs).816The central theme of secondary preventive approaches

in natural disasters is that, although primary prevention oftheexposure may not be technically feasible (e.g., the sourcebeing an unpreventable and relatively unpredictable event,such as a volcanic eruption), it may be possible to reduce theshort- and long-term adverse impact of such a disasterthrough multidisciplinary planning, response, and relief mea-sures.

In this Chapter, we provide a review of the literatureprior to May 18, 1980 concerning the adverse health effectsof volcanic eruptions. Following that, we describe the globaldistribution and occurrence of explosive and effusive (con-sisting primarily of emission of gases and lava) volcaniceruptions. We provide a brief discussion of the public healthimplications for areas at high- and low-risk, with emphasis onthe implications of explosive volcanism in developing coun-tries. The purpose is to provide data which may be used asthe basis for pre-disaster planning and preparedness in areasof the world where explosive and effusive volcanic eruptionsare relatively common in proximity to vulnerable humanpopulations.'-3'8-2

A Review of the LiteratureThe World Health Organization has defined adverse effects

on human health to include those hazards which cause signif-icant impairment ofmental and physical health. 17 The AmericanThoracic Society has proposed a set of guidelines as to whatconstitutes an adverse respiratory effect.'8 Volcanic hazardsmay be characterized by their impact on health as direct orindirect, and by their time of onset as immediate or delayed."4The general classes of volcanic hazards and some of thebiologically plausible adverse effects on safety, health, andwell-being within each class are outlined in Table 1.Immediate Psychosocial and Economic Effects

For the most part, the human hazards traditionallyexamined in relation to volcanic activity have been limited tothe direct and immediate (traumatic, psychosocial, andeconomic) effects of peri-eruptive events such as ashfalls,explosive blasts, pyroclastic flows (high speed blasts of hotgases and ash), lightning, lava flows, and mud flows.24 Therehave been reports of dysfunctional behavioral responses tothe extreme psychosocial and economic stresses which mayprecede or follow a major natural disaster.' 116"19 However,few studies have provided detailed accounts of the impact ofexplosive volcanism on the psychosocial and economicwell-being of industrialized societies.20 An exception was therecent monograph on the eruptions of Mount Usu inHokkaido, Japan in 1977.21 22(18)* In the latter investigations,the only adverse effects attributed to the eruptions weretransient increases in anxiety, insomnia, and irritations oftheeyes and upper respiratory tract.

Community residents may experience varying degrees ofpsychosocial stress, depending on poorly understood per-sonal risk factors and the degree to which they and their lovedones are adversely affected. In addition, health professionalsand community leaders often experience stress associatedwith choosing between their professional duties and theirfamily commitments.2"19'20

*Parenthetic superscript number refers to that numbered report withinreference 22.

TABLE 1-Hazards to Human Saety, Health, and Well-being from Ex-plosive Volcanic Act1vIty

General Class ofHazards Specific Examples of Plausible Effects

Direct and Immediate * Safety hazards from the effects of blasts,pyroclastic or lava flows, and earthquakes.

Direct and Delayed

Indirect and Immediate

Indirect and Delayed

* Health hazards from inhalation exposure tointense airborne concentrations of ash andgases (e.g., irritation of the respiratory tractby SO2, HCI, or HF; exacerbation ofpreexisting bronchial hyperreactivity,obstructive airways diseases, orcardiopulmonary diseases; asphyxiation byCO2 or intoxication by H2S or CO; andsuffocation by volcanic ash) or fromingestion of water contaminated with toxicamounts of volcanic minerals (e.g., fluoride,mercury, or arsenic).

* Psychosocial, environmental, and economichazards from rumors or uncertainties aboutcurrent or future hazards; from disruption ofroutine services; by displacement of largenumbers of people into refugee camps; andfrom destruction of property.

* New onset, exacerbation, or acceleration ofnon-communicable respiratory diseasesfrom frequent, intense, or prolongedexposures to toxic gases and/orrespirable-size ash.

* Safety hazards from mud flows, flash floods,lightning-induced fires, and tsunamis.

* Health hazards from epidemic outbreaks ofendemic diseases due to disruption ofroutine environmental, public health, andmedical services.

* Health hazards from increases in thepathogenic potential of infectious and toxicpulmonary pathogens due to the irritant andtoxic effects of volcanic gases and ash onthe lung's defense mechanisms.

* Psychosocial, economic, and public healthproblems resulting from intense orprolonged disrupfton of society and theenvironment.

'Effusive (Hawaiian) types of volcanic activity result in three general types of potentialhazards: 1) safety hazards from lava fountains, lava flows, or earthquakes; 2) health hazardsfrom emiion of volcanc gases or from the combustion products of forest fires caused bylava and hot gases; and 3) psychosocial and economic hazards from the effects of volcanicactivity on prOperty, agriculture, horticulture, and air quality.1481'-13

The literature concerning the epidemiology of mentalhealth effects of disasters is reviewed in more detail inchapter 9 by Shore, et al, and elsewhere.'9'23Immediate Mortality Effects

In the period 1600-1980, about 161,000 deaths (67 percent of the 238,900 for which data exist) have resulted fromvolcanic eruptions in Indonesia; 31,000 (13 per cent) in theCaribbean Region; 19,000 (8 per cent) in Japan; 9,400 (4 percent) in Iceland; and only 19,000 (8 per cent) in all other areasof the world.2 During all but the last 30-50 years of thisperiod, the historical record concerning causes of death hasbeen very unreliable because of temporal trends in the:

* frequency of eruptions of specific volcanoes and thevulnerability of nearby human settlements;

* likelihood of investigating and reporting the effects of

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EPIDEMIOLOGICAL ASPECTS OF VOLCANISM

TABLE 2-Proportion of Reported Deaths due to Specific VolcanicHazards*

1600-1982 1900-1982Total Deaths Total Deaths

Volcanic Hazards (%) (%)

Pyroclastic Flows** and 55,000 (23.0) 36,800 (70.4)Debris Avalanches

Mudflows (Lahars) 14,700 (6.2) 6,400 (12.2)Ashfalls (Tephra) and 11,000 (4.6) 3,000 (5.7)

Ballistic ProjectilesDiseases and Starvation# 95,300 (39.9) 3,200 (6.1)Tidal Waves 44,000 (18.6) 400 (0.8)

(Tsunamis)"5Lava Flows 1,000 (0.4) 100 (0.2)Gases and Acid Rains 200 (0.1) 200 (0.4)Other or Unknown 17,300 (7.2) 2,200 (4.2)

HazardsTotal 238,900 (100) 52,300 (100)

*Adapted with permission from Tables 3.2 and 3.3 in Blong RJ: Vokanic Hazards: ASourcebookon the Effects ofEruptions.2 Reported deaths have been rounded to the nearesthundred and certain categories have been combined.

^*Pyroclastic flows (and, possibly ashfalls) have caused a large proportion of thereported deaths in two eruptions between 1600 and 1980: about 10 per cent (3,600 deaths)in the 1883 eruption of Krakatau, Indonesia, and nearly 100 per cent (29,000) in the 1902eruption of Mount Pelee, Martinique. A debris avalanche (cone collapse) caused about 70per cent of the 10,000 deaths at Mount Unzen, Japan in 1792. Altogether, three eventscaused about 77 per cent (42,600) of the deaths attributed to this volcanic hazard in thisperiod of time.

,Diseases and/or starvation have caused a large proportion of reported deaths in twoeruptions between 1600 and 1980: nearly 100 per cent (9,400) in the 1783 eruption of Laki,Iceland, and about 90 per cent (82,800) in the 1815 eruption of Tambora, Indonesia.Altogether, these two events caused about 97 per cent (92,200) of the deaths attributed tothis volcanic hazard in this period of time.

#Tidal waves have caused a large proportion of reported deaths in two eruptionsbetween 1600 and 1980: about 30 per cent (4,300) in the 1972 eruption of Mount Unzen,Japan, and about 90 per cent (32,800) in the 1883 eruption of Krakatau, Indonesia.Altogether, these two events caused about 84 per cent (37,100) of the deaths attributed tothis volcanic hazard in this period of time.

explosive volcanism, regardless of the size and proximityof nearby human settlements; and

0 validity and reliability of establishing causes of mor-bidity and mortality in relation to specific types of volcanichazards.From Table 2, it can be appreciated that certain hazards,

directly related to explosive eruptions (pyroclastic flows,debris avalanches, and volcanic mudflows), have been con-sistently associated with a large proportion of deaths.Ashfalls have been consistently associated with a lesser butsubstantial proportion of deaths due to volcanic hazards.Other, more indirect, volcanic hazards (especially disease,starvation, and tidal waves) have had a disproportionateimpact on mortality over this period as a result of causingenormous numbers of deaths in only a few eruptions or indeveloping countries.2 In the 1985 eruption of the Nevada delRuiz volcano in Colombia, South America, an estimated28,000 persons were killed by mud slides. This changes theproportion of deaths in the last column of Table 2 substan-tially and illustrates how factors other than volcanic hazardscan influence eruption-related mortality (see also Chapter3).1-4,141620,23

Scalding due to blasts of superheated steam and ash aswell as suffocation due to inhalation of massive quantities ofairborne ash were the reported causes of thousands of deathsfollowing explosive volcanic eruptions.4,24 However, de-tailed clinical, pathological, and epidemiological studies ofsurvivors25 and victims26 of pyroclastic flows and volcanicash-induced suffocation were not available prior to the 1980eruptions of Mount St. Helens. Furthermore, the mortalitydata in Table 2 were not available as rates among definedpopulations at risk. Thus, it is difficult to interpret these data

TABLE 3-Natural Hazards Statistics In the West Indies, with GlobalComparisons*

Type of Natural Hazard

Statistic (1680-1979) Eruption Hurricane Earthquake

Total Fatalities 30,621 30,803 15,912Number-of Major Events 3 21 8Average Size of Exposed

Population 56,000 4,200,000 4,200,000Average Fatality Rate amongExposed 1/550 1/41,000 1/79,000

Largest Loss of Ufe in One Event 29,000 15,626 5,500(World's largest loss in one event) (92,000) (500,000) (830,000)

*Adapted with permission from Tomblin JF: Earthquakes, volcanoes, and hurricanes:a review of natural hazards and vulnerability in the West Indies.' Historical losses from floods(other than as a direct result of hurricanes) have not exceeded 231 in a single event in theWest Indies.

without information about demographic, occupational, geo-graphic, and other risk factors.2

Some of the most reliable natural hazards data areavailable for the West Indies' where it is of interest tocompare the magnitude of fatalities caused by volcaniceruptions with the impact of other natural disasters (Table 3).The differences in fatality rates may be due to importantregional variations in the relative frequency and magnitude ofdestructive natural disasters and in the vulnerability ofpopulations on affected Caribbean islands.' On a globalrather than a regional scale, the rates for mortality due tospecific types of natural disasters have not been adequatelydescribed. However, it is interesting to note that during thesame period (1600 to 1980), earthquakes alone caused aboutfive million deaths-20 times the number of deaths due toeruptions.1"2Immediate Morbidity Effects

A number of reports available before May 1980 haddocumented the transient, acute irritant effects of volcanicash and gases on the mucous membranes of the eyes andupper respiratory tract as well as the exacerbation of chroniclung diseases during, and for some time after, eruptions withheavy ashfall.27-30 The apparent new onset of transientbronchospastic airways disease in a number of previouslywell infants was reported for the first time following theeruptions of La Soufriere volcano in 1979.31 However, theprevalence of asymptomatic bronchial hyperreactivity32,33was unknown among the population at risk prior to theirexposures to volcanic ash.

Reported transient, acute health effects have not beenlimited to the eyes and respiratory tract. Major geophysicaldisasters (such as earthquakes and volcanic eruptions) havebeen associated with epidemic outbreaks of endemicwaterborne diseases.34'35 However, the increased intensity orquality of epidemiologic surveillance for a wide variety ofadverse health effects in the aftermath of such disasters mayhave resulted in the identification of some pseudoepidemics.Delayed Morbidity Effects

With respect to the risk of chronic respiratory or otherdiseases, there have not been any population-based studies ofthe occurrence and distribution of such disease in relation tovolcanic emissions. The occupational health literature con-tains several examples of tuffaceous (related to volcanic tuff,tephra, or ash) pneumoconioses.3638 However, reports ofthese pulmonary disease-which include radiographic,spirometric, and serological abnormalities-have generally


BERNSTEIN, ET AL.

been published in monographs or conference proceedingswithout critical peer review, or with very little detail con-cerning methodology. The Canneto-Lipari pumice stoneworkers in Messina, Italy are reported to have developed aserious form of pneumoconiosis within a few years todecades of initial exposures.26 The highly respirable volcanicdust, produced during processing of pumice stones, report-edly contains only 1.2 per cent to 5 per cent free crystallinesilica (in the form of quartz). However, industrial hygienesurveys indicated that the mean exposure levels were quitehigh, reported as 2.5 to 3.1 million particles per cc, of which78-93 per cent were less than 5 ,um in diameter by count.37

The risk of developing silicate pneumoconiosis fromprolonged exposure to volcanic ash is presently un-known;8"1123943 however, silicate pneumoconioses havebeen described and well-documented among humans " "

and other primates47 who reside in dry, dusty environments.The extent to which these roentgenographic abnormalitiesare attributable to low-level contamination of silicates withfree crystalline silica, asbestiform minerals, or other toxicagents which may be found in volcanic ash is not wellknown. 1',40,48

The Russian literature contains several references (byone author) concerning the release of carcinogenic hydro-carbons by volcanic action.49 Polycyclic aromatic hydrocar-bons are released whenever any complex organic material isburned, for example in forest fires which may result fromvolcanic activity.50 Prior to the eruptions of Mount St.Helens, the potential hazards associated with the release ofradon gas and its short-lived radioactive decay products hadnot been studied in detail in explosive volcanic eruptions.5'

The chronic disease hazard which is most convincinglyassociated with volcanic activity is the excess occurrence ofenvironmental respiratory disease in the Cappodocia area ofcentral Anatolia, Turkey.52-5 Over a period of many years, thevolcanic tuff in this region was geochemically transformed tofibrous asbestiform minerals. Inhalation and ingestion of theresulting erionite and tremolite fibers have been associated witha very high incidence of pleural plaques and malignantmesothelioma among the residents of villages in this area.Another example of environmental respiratory disease, possi-bly caused by inhalation of tremolite fibers of volcanic origin,has been reported from northwestern Greece where pleuralcalcifications and other pathognomonic pulmonary lesions oc-cur endemically among the general population.55'5

It is clear that many years after the eruption of a volcanohas ended, environmental exposure to the transformationproducts of volcanic minerals (e.g., asbestiform minerals ofcarcinogenic dimensions)57 can cause serious and even wide-spread chronic diseases. However, the theoretical possibilitythat freshly erupted volcanic ash could contain harmfulamounts of respirable-size crystalline free silica or fibrousminerals had not been actively investigated prior to theeruptions of Mount St. Helens. "'l40Unconfirmed Effects

Among the more exotic reported adverse health effectsof volcanic ash, there is a continuing controversy over theetiology of endemic non-infectious (non-filarial) elephanti-asis.58 There are also undocumented reports of excessivenephropathy and urinary tract cancers59 in areas of priorvolcanic activity where large segments ofthe population walkbare-footed on volcanic soils or drink water containingsilicates and leachates from volcanic rocks.

Identifying High-Risk Areas for HazardsGlobal Distribution of Explosive Volcanoes

Volcanologists have devised the Volcanic ExplosivityIndex (VEI) as a measure of explosive vigor by combiningquantitative (volume of ejected products, distance to whichejecta were thrown, eruptive cloud height, etc.) and qualitativedata to yield a simple #O-to-#8 index of increasing explosiv-ity.60 In deriving a VEI rating for an eruption at a particularvolcano, eruptions are counted separately only when theyfollow a preceding eruption at the same volcano by more thanthree months. Explosive volcanoes which have had historicallyrecorded eruptions of VEI -#3 are among those which areconsidered "active" and most dangerous to public health andsafety.60 See chapter 2 for further information on the hazards ofexplosive and effusive volcanoes.8"''-13,61

At the margins of the continents surrounding the PacificOcean, the slow subduction of the Pacific tectonic platesunder the continental plates has formed a large ring of activeexplosive volcanoes. The so-called "Ring of Fire" contains221 (80 per cent) of the 275 volcanoes of the world which areconsidered potentially active and have had historical erup-tions with VEI greater than or equal to a VEI= #3 (i.e.,"moderate to large eruptions of 107 to 108 cubic meters ormore of ejecta in severe explosions").'

Figure 1 shows the numberof active explosive volcanoeseach area or nation in the Ring of Fire contains; it includesonly those volcanoes which have been historically reportedto have erupted one or more times since the year 1000 witha force of VEI -#3. In descending order, Japan and theMariana Islands have the greatest number (39) and the WestCoast of Canada and the US the smallest number (5).

This region accounts for 238 (87 per cent) of the world'sactive volcanoes with VEI -#3 eruptions if it is consideredto include the contiguous (but, non-"Ring") volcanic areas ofAsia (13 such volcanoes are located in parts of China, Korea,and the USSR-mostly in the Kamchatka peninsula) and theWest Indies (4). There are several active effusive volcanoeson the Hawaiian islands, but only one eruption of a Hawaiianvolcano (Kilauea in the year 1790) exceeded a VEI of #3during historic times.13'24

Although temporal trends in reporting explosive volcan-ism have made the historical record very unreliable prior to1950, since that time a VEI >#3 eruption has been reportedsomewhere in the world every few months (a rate of about5-10 such explosive eruptions per year).60Y24Java, Indonesa: A Developing Country at High Risk

Of the "Ring" nations' 221 volcanoes with VEI -#3eruptions, 6 per cent (13) are on the island of Java whichcontains more than 60 per cent of Indonesia's 140 millioninhabitants in an area about the size of California. The 13volcanoes ofJava with VEI -#3 eruptions have accounted for51 (43 per cent) of the 118 VEI .#3 explosive volcaniceruptions historically recorded in Indonesia since the year 1000.

The reported frequency of VEI .#3 eruptions at each ofthe 37 individual Indonesian volcanoes ranges from about0.2/100 years to 2.9/100 years (or, on average, four eruptionsevery 500 years). There have been periods of clustered fatalexplosive eruptions of varying magnitude on the VEI scale.For example, since 1960, there have been 10 eruptionscausing fatalities at nine separate Indonesian area volcanoes.Five separate volcanoes on Java contributed to these 10 fataleruptions between 1966 and 1982.

A number of the world's most destructive and deadlyvolcanoes (Table 2) are located on the islands of Indonesia,

AJPH March 1986, Vol. 76, Supplement6


FIGURE 1-A Mercator Projection of the Active Explosve Volcanoes In the "Ring of Fire."SOURCE: Simkin, et al."8

including the only volcano with a VEI= #7 eruption(Tambora), as well as Krakatau (maximum VEI= #6),Galunggung (max. VEI= #5), merapi (max. VEI= #4),Agung (max. VEI= #4), and Kelut (max. VEI= #4). In 1883,a VEI= #6 eruption of Krakatau killed over 36,000 people.24

The relative frequency and intensity ofexplosive volcan-ism in densely populated areas of developing countries likeIndonesia may represent substantial public health problems.It is in countries where routine public health services, waterquality, nutrition, and housing are marginally adequate thatthe adverse health impact of extensive environmental dam-age associated with volcanic activity will be the most se-vere.14'81112'20 It is also possible, by analogy to miningpopulations,62 that frequent or intense exposures to highlyrespirable silicates and free silica in volcanic ash mayexacerbate endemic chronic respiratory diseases (e.g., tu-berculosis, which is still highly prevalent in Indonesia).8'63Western North America: An Industialized Country at RelatdvelyLow Risk

The US Geological Survey (USGS) has recently releaseda preliminary assessment of more than 35 volcanoes in the

western United States and Alaska that are likely to erupt "inthe future. -64'65

Of these, the group of greatest concern includes thosewhich have had explosive eruptions on an average of every200 years or less, or have erupted within the past 300 years,or both. This most hazardous group consists of Mount St.Helens, the Mono-Inyo Craters, Lassen Peak, Mount Shasta,Mount Rainier, Mount Baker, and Mount Hood. The nextgroup includes volcanoes which have erupted less frequentlythan every 1,000 years and last erupted more than 1,000 yearsago; the third group includes those volcanoes that lasterupted more than 10,000 years ago but overlie large magmachambers.65 Many of these volcanoes underlie or are veryclose to logging and agricultural communities or popularresorts and recreational areas.

Prior to the 1980 eruptions of Mount St. Helens, therewere no reports of fatalities directly attributed to explosivevolcanism in the United States.24 In fact, since the signing ofthe Declaration of Independence, explosive volcanic activityin the territory now known as the States of California,Oregon, and Washington has consisted of only minor asheruptions at Mount Hood (in 1906); several more spectaculareruptions at Lassen Peak (1914-17); and a period of clustered


BERNSTEIN, ET AL.

or prolonged eruptions at four Cascade volcanoes locatedwithin 40-350 km of each other (Mounts Baker, Rainier, St.Helens, and Hood, from 1832 to 1880).24 During the latterperiod, all four of the volcanoes erupted ash or lava for up to30 years, sometime erupting in the same year.24,64,65

The geologic record gives evidence of eruptive activityat Mount St. Helens dating from about 40,000 years ago.24 In1975, Crandell, Mullineaux, and Rubin reported that thevolcano had never been dormant for more than about fivecenturies at a time since 2500 BC and that dormant periodsof one or two centuries, or less, were more typical.' Theypredicted that the volcano, last active for a 27-year periodfrom 1831 to 1857, "will erupt again-perhaps within the nextfew decades." With the exception of the landslide, lateralblast, and widespread distribution of volcanic ash, theydescribed precisely the very hazards which eventually re-sulted from the eruption of May 18, 1980. Unfortunately, upuntil the moment that the cataclysmic eruption began, itstiming could not be precisely predicted.

It is clear that explosive activity at Cascade volcanoescould have very different socioeconomic, health, and safetyconsequences today than in the 19th and early 20th century(e.g., if Mount St. Helens' lateral blast of May 18, 1980 hadoccurred in the midst of a work day for logging companiesinstead of early on a Sunday morning or if the direction of theblast had been toward the heavily populated west instead ofthe rural northeast). Accordingly, the USGS has establisheda Volcano Hazards Program to improve their ability tomonitor and predict the behaviors of these volcanoes withsufficient lead time for reasoned decision-making about landuse, access restrictions, evacuations, and other matters.64Hawaii and Nicaragua: Areas with Frequent and Prolonged EffusiveVolcanism

As of this writing (February 1985), the 30th episode ofthe most recent series of eruptions at Hawaii's KilaueaVolcano has continued to cause potentially hazardous humanexposures to lava flows and volcanic gases, primarily sulfurdioxide, SO2.'3 During eruptive periods such as the currentseries which began on January 3, 1983, emissions of SO2increase about 10-fold over the usual 50-150 metric tons perday released from active vents of Mona Loa and Kilaueavolcanoes. Eruptive periods with increased SO2 emissionsoccur on the average at these volcanoes every four years andevery three years, respectively. While no evidence forexcessive mortality or clinically significant respiratory mor-bidity due to noncommunicable chronic respiratory diseaseswas found in association with the first few weeks of Kilauea'srecent eruptions, it was noted that routine environmentalmonitoring for SO2 takes place at rooftop locations upwind ofthese uncontrollable "stationary" sources of potentiallyhazardous air pollutants.'3

Roughly every 25 years, Masaya volcano in Nicaraguaundergoes extensive degassing that lasts for 5-10 years.During these prolonged episodic emissions, from a healthstandpoint, the principal gases emitted (and approximatemean volumes in metric tons per day) are S02 (1,300),hydrogen chloride (400), and hydrogen fluoride (5). Sulfateaerosol levels as high as 400 ,ug/m3 and SO2 levels of 1 ppmare regularly found at ground level in populated areas 30 kmdownwind from the plume.61**

**The National Ambient Air Quality Standard Action Levels of the USEnvironmental Protection Agency call for "alert" at 2-hour average concen-trations of 375 F&g/m3 (for total suspended particulates derived from fossil fuelcombustion). The World Health Organization's 24-hour Permissible Exposure

8

Corrosive effects on property and economic losses toagriculture have been documented in Nicaragua, Hawaii,Iceland, and other areas affected by frequent or prolongedeffusive volcanic activity; however, no valid and reliable dataon the population-based occurrence and distribution of ad-verse respiratory effects have been obtained in these areas inrelation to routine emissions and episodic eruptive activi-ty.'3'6' The health and safety hazards of effusive volcanismare not the subject of this monograph, but are reviewedelsewhere.8" 1-13,61

Explosive Voanism: Research Needs in Disaster Preparedness andMitigation

The immediate public health responses and detailed fieldand laboratory investigations of respiratory, ocular, andpsychosocial effects detailed in this monograph may not berelevant or generalizable to developing countries with limitedresources and substantial endemic health problems. In theseareas of relatively frequent explosive volcanism (see Figure1), there remain many uncertainties in our knowledge aboutthe factors which will prevent or reduce vulnerability tovolcanic hazards.

In a recent book, Volcanic Hazards: A Sourcebook onthe Effects ofEruptions, Blong has characterized numerousaspects of the unreliability of available morbidity and mor-tality data.2 Limitations to the completeness and accuracy ofthe data in Table 2 illustrate some of the problems inherentin drawing conclusions from these data about effective publichealth preventive measures other than the logical ones whichmay be established by consultation between volcanologistsand the public health officials:1414

* Strict pre-disaster restrictions on siting human settle-ments;* Strict restrictions on access for recreational and com-

mercial purposes during recognized premonitory activity;and* Timely and well-executed evacuation of vulnerable

settlements to safe and healthful temporary refugee campsfollowing specific or accelerating premonitory events.

Thus, when premonitory events prompt affected coun-tries to seek volcanologic technical assistance in monitoringand predicting seismic activity, it may be advisable for amultidisciplinary team of experts in environmental health,geology, and epidemiology to be assembled on site to provideadvice about primary and secondary preventive measuresand to plan applied public health research activities forevaluating the effectiveness of these measures.

REFERENCES1. Tomblin JF: Earthquakes, volcanoes, and hurricanes: a review of natural

hazards and vulnerability in the West Indies. AMBIO 1981; 10:340-345.2. Blong RJ: Volcanic Hazards: A Sourcebook on the Effects of Eruptions.

North Ryde, New South Wales, Australia: Academic Press, 1984.3. Macdonald GA: Volcanological aspects. In: Disaster Prevention and

Mitigation: A Compendium of Current Knowledge, Vol. 1, Pub. No.GE.77-6194 (7828). Geneva: United Nations Disaster Relief Co-ordinator(UNDRO), 1976.

4. WalkerGPL: Volcanic hazards. Interdisciplinary Sci Rev 1982; 7:148-157.5. Rosenfeld CL: Observations on the Mount St. Helens eruption. Am Sci

1980; 68:494-509.6. Decker R, Decker B: The eruptions of Mount St. Helens. Sci Am 1981;

244:68-80.7. Swanson DA, Casadevall TJ, Dzurisin D, Malone SD, Newhall CG,

Weaver CS: Predicting eruptions at Mount St. Helens, June 1980 throughDecember 1982. Science 1983; 221:1369-1376.

8. Bernstein RS, Buist AS: Public health aspects of volcanic hazards:evaluation and prevention of excessive morbidity and mortality due to

Limit for S02 is 0.05 ppm.13'61

AJPH March 1986, Vol. 76, Supplement

natural disasters. Disasters 1984; 8:6-8.9. Western KA: Epidemiologic Surveillance after Natural Disaster. Pub. No.

420. Washington, DC: Pan American Health Organization, 1982.10. Seaman J, de Ville de Goyet C, Donaldson D, Bulle W: Emergency Health

Management after Natural Disaster. Sci. Pub. No. 407. Washington, DC:Pan American Health Organization, 1981.

11. Baxter PJ, Bernstein RS, Falk H, French J, Ing R: Medical aspects ofvolcanic disasters: an outline of the hazards and emergency responsemeasures. Disasters 1982; 6:268-276.

12. Baxter PJ: Health hazards of volcanic eruptions. J R Coll Phys Lond 1983;17:180-182.

13. Bernstein RS, Falk H, Greenspan J, Anderson B, Weisner PJ, Conrad JL,Bomgaars M: Assessment of respiratory hazards associated with airpollutants from volcanic eruptions, Kilauea Volcano, Hawaii. Atlanta:Centers for Disease Control, EPI-83-23-2, July 1984.

14. White GF (ed): Natural Hazards: Local, National, Global. London:Oxford University Press, 1974.

15. Mileti D, Drabeck T, Haas G: Human Systems in Extreme Environments:A Sociological Perspective. Boulder: University of Colorado Press, 1975.

16. Quarantelli E, Dynes R: When disaster strikes. Psychol Today 1972;5:67-70.

17. World Health Organization: Early Detection of Health Impairment inOccupational Exposure to Health Hazards. WHO Tech. Rep. Series No.571. Geneva: WHO, 1975.

18. American Thoracic Society Committee of the Scientific Assembly onEnvironmental and Occupational Health: Guidelines as to what constitutesan adverse respiratory health effect, with special reference to epidemio-logic studies of air pollution. Am Rev Respir Dis 1985; 131:666-668.

19. Melick ME, Logue IN, Frederick CJ: Stress and disaster. In: GoldbergerL, Bresnitz S (eds): Handbook of Stress-Theoretical and ClinicalAspects. New York: Free Press, 1982.

20. Sheets PD, Grayson DK: Volcanic Activity and Human Ecology. NewYork: Academic Press, 1979.

21. Seki K (ed): Usu Eruption and Its Impact on the Environment. (Englishtranslation provided by Dr. John Hada and the Federal EmergencyManagement Agency.) Hokkaido, Japan: Hokkaido University, 1978.

22. Falk H, Baxter PJ, Ing R, French J, Heath CW, Bernstein RS, MerchantJA: CDC-Mount St. Helens Volcano Health Reports #1-23. Atlanta:Centers for Disease Control, May 30, 1980 to February 23, 1981.

23. Logue JN, Melick ME, Hansen H: Research issues and directions in theepidemiology of health effects of disasters. Epidemiol Rev 1981;3:140-162.

24. Simkin T, Siebert L, McClelland L, Bridge D, Newhall C, Latter JH:Volcanoes of the World: A Regional Directory, Gazeteer, and Chronologyof Volcanism during the Last 10,000 Years. Stroudsburg, PA: HutchinsonRoss Publishing (for Smithsonian Institution), 1981.

25. Parshley PF, Kiessling PJ, Antonius JA, Connell RS, Miller SH, GreenFHY: Pyroclastic flow injury: Mount St. Helens, May 18, 1980. Am J Surg1982; 143:565-568.

26. Eisele JW, O'Halloran RL, Reay DT, Lindholm GR, Lewman LV, BradyWJ: Deaths during the May 18, 1980 eruption ofMount St. Helens. N EnglJ Med 1981; 305:931-936.

27. Hovey EO: Martinique and St. Vincent: a preliminary report upon theeruptions of 1902 at Mt. Pelee and Mt. La Soufriere. Bull Am Museum NatHist 1902; 16:333-372.

28. Horton RJM, McCaldin RO: Observations on air pollution aspects ofIrazuVolcano, Costa Rica. Public Health Rep 1964; 79:925-929.

29. da Corogna M: The influence upon the health ofman and vegetation fromvolcanic emissions of Santorin Volcano. Compt Rend Acad Sci (Paris)1866; 62:1381-1385.

30. Du Val Brecht N: Medical relief during a volcanic eruption. Milit Surg1913; 32:149-152.

31. Leus X, West CM: Asthmatic bronchitis associated with a volcaniceruption in St. Vincent, West Indies. Disasters 1981; 5:67-69.

32. Boushey HA, Holtzman MJ, Sheller JR, Nadel JA: Bronchial hyper-reactivity. Am Rev Respir Dis 1980; 121:389-413.

33. Weiss ST, Tager IB, Weiss JW, Munoz A, Speizer FE, Ingram RH:Airways responsiveness in a population sample ofadults and children. AmRev Respir Dis 1984; 129:898-902.

34. Bardswell N: Volcanic action as a cause of outbreaks ofepidemic disease.Edinburgh Med J 1901; 10:321-335.

35. Weinger BG, Blaser MJ, Gedrose J, Lippy EC, Juranek DD: An outbreakof waterborne giardiasis associated with heavy water runoff due to warmweather and volcanic ashfall. Am J Public Health 1983; 73:868-872.

36. Faraone G, Majori I: Conimetric and granulometric determinations invarious operating phases in the pumice stone industry in Canneto-Lipari(Messina). Acta Med Legal et Social 1958; 11:83-94.

37. Babolini G, Inferrera C, Girbino G, Grosso M: The clinical and morpho-anatomic aspects of the liparitosis. In: Condorelli L, Teodori U, Anguis-sola AB, Sangiorgi M (eds): Proceedings of the XIV International

AJPH March 1986, Vol. 76, Supplement


Congress of Internal Medicine, Rome, October 15-19, 1978 (Part 2).Oxford: Excerpta Medica, 1980; 829438.

38. Dashtoyan AK, Akopyan SG, Azoyan IS, Magakyan KI: Respiratoryfunction in the early stages of tuffaceous pneumoconiosis. Gig Tr ProfZabol 1980; 2:36-37.

39. Green FHY, Vallyathan V, Mentnech MS, et al: Is volcanic ash apneumoconiosis risk? Nature 1981; 293:216-217.

40. Bernstein RS, McCawley MA, Attfield MD, et al: Epidemiologic assess-ment of the risk for adverse pulmonary effects from persistent occupa-tional exposures to Mount St. Helens' volcanic ash (tephra). In: KellerSAC (ed): Mount St. Helens: One Year Later. Cheney, WA: EasternWashington University Press, 1982; 207-213.

41. Merchant JA, Baxter PJ, Bernstein RS, et al: Health implications of theMount St. Helens eruption: epidemiological considerations. Ann OccupHyg 1982; 26:911-919.

42. Buist AS: Are volcanoes hazardous to your health? West J Med 1982;137:294-301.

43. Craighead JE, Adler KB, Butler GB, Emerson RJ, Mossman BT,Woodworth CD: Biology of disease: health effects of Mount St. Helensvolcanic dust. Lab Invest 1983; 48:5-12.

44. Goyal RK: Pneumoconiosis in the non-industrial population of Rajasthan.J Indian MA 1958; 30:79-82.

45. Sherwin RP, Barman ML, Abrahams JL: Silicate pneumoconiosis of farmworkers. Lab Invest 1979; 40:576-582.

46. Glyseth B, Stettler L, Mowe G, Skaug V, Lexow V: A striking depositionof mineral particles in the lungs of a farmer: a case report. Am J Ind Med1984; 6:231-240.

47. Brambilla C, Abrahams JL, Brambilla E, Benirschke K, Bloor C:Comparative pathology of silicate pneumoconiosis. Am J Pathol 1979;%:149-163.

48. Langer AM: Mineral dust and pulmonary lesions: etiological link ofepiphenomenon? Am J Ind Med 1984; 6:169-171.

49. llnitsky AP, Belitsky GA, Shabad LM: On the carcinogenic polycycicaromatic hydrocarbon, benzo(a)pyrene, in volcano exhausts. CancerLetter 1976; 1:291-294.

50. Suess MJ: The environmental load and cycle of polycyclic aromatichydrocarbons. Sci Total Environ 1976; 6:239-250.

51. Fruchter JS, Robertson DE, Evans JC, et al: Mount St. Helens ash fromthe May 18, 1980 eruption: chemical, physical, mineralogical, and biolog-ical properties. Science 1980; 209:1116-1125.

52. Baris YI, Artvinli M, Sahin AA: Environmental mesothelioma in Turkey.Ann NY Acad Sci 1979; 330:423-432.

53. Artvinli M, Baris YI: Malignant mesotheliomas in a small village in theAnatolian region ofTurkey: an epidemiologic study. JNCI 1979; 63:17-22.

54. Rohl AN, Langer AM, Moncure G, Selikoff IJ, Fischbein A: Endemicpleural disease associated with exposure to mixed fibrous dust in Turkey.Science 1982; 216:518-520.

55. Bazas T, Bazas B, Kitas D, Gilson JD, McDonald JC: Pleural calcificationin northwest Greece. Lancet 1981; 2:254.

56. Constantopoulos SH, Goudevenos JA, Saratzis N, Langer AM, SelikoffU, Moutsopoulos HM: Endemic pleural calcification in north-westernGreece associated with environmental exposure to mineral fiber. EnvironRes 1984; (in press).

57. Halrington JS: Fiber carcinogenesis: epidemiologic observations and theStanton hypothesis. JNCI 1981; 67:977-989.

58. Price EW, Henderson WJ: Silica and silicates in femoral lymph nodes ofbare-footed people in Ethiopia with special reference to elephantiasis ofthe lower limbs. Trans Roy Soc Trop Med Hyg 1979; 73:640-647. See also:editorial (1:349) and an exchange of letters to the editor (1:1419; 2:267),Lancet 1980.

59. Markovic B: Endemic nephropathy and cancer of the upper urinary tracturothelium in Yugoslavia. Israel J Med Sci 1972; 8:540-548.

60. Newhall CG, Self S: The volcanic explosivity index (VEI): an estimate ofexplosive magnitude for historical volcanism. J Geophys Res 1982;87: 1231-1238.

61. Baxter PJ, Stoiber RE, Williams SN: Volcanic gases and health: MasayaVolcano, Nicaragua. Lancet 1982; 2:150-151.

62. Snider DE: The relationship between tuberculosis and silicosis. Am RevRespir Dis 1978; 118:455-460.

63. Vallyathan V, Reasor M, Stettler LE, Robinson V, Bernstein RS:Comparative in vitro cytotoxicity of volcanic ashes from Mount St.Helens, El Chichon, and Galunggung. J Toxicol Environ Health 1984;14:641-654.

64. Bailey RA, Beauchemin PR, Kapinos FP, Klick DW: The VolcanoHazards Program: Objectives and Long-Range Plans. US GeologicalSurvey Open-File Report 83-400, 1983.

65. Kerr RA: Volcanoes to keep an eye on. Science 1983; 221:634635.66. Crandell DR, Mullineaux DR, Rubin M: Mount St. Helens Volcano:

Recent and future behavior. Science 1975; 187:438-441.

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introduction to the epidemiological aspects of explosive

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