V. HEALTH EFFECTS ASSESSMENT
This section examines the health effects issues associated with exposure to the contaminants contained in oil fire smoke. Based on a review of the scientific literature, it determines whether there is likely to be a relationship between measured contaminant concentration levels observed in the Gulf and the adverse health effects reported by some US troops. Information contained in this section includes, in part, the results of a literature review on Gulf War illnesses conducted by the RAND Corporation. The RAND report focused on four main areas: 1) the identification of contaminants present and their measured concentrations in the Kuwait theater of operations, 2) a comparison between observed contaminant levels and US ambient and occupational exposure standards, 3) the possible health effects to humans exposed to those pollutant levels as cited in the literature, and 4) an examination of how these effects compare to symptoms observed or reported by veterans.
The scope of the RAND report involved comprehensive library searches that yielded about 2,500 titles of scientific papers published, or in press, in peer-reviewed journals. Of these, about 500 abstracts were examined and about 250 peer-reviewed papers that were read and analyzed. Other reference documents included government publications, books, conference proceedings and reports from US and international agencies and institutions.
In addition to the RAND report, information from other sources on health effects associated with this type of exposure was used as appropriate to complete this section.
B. Contaminant Levels
As noted in Section IV, monitoring results identified numerous contaminants in the oil fire smoke, including carbon dioxide (CO2), carbon monoxide (CO), oxides of sulfur (SOX) and nitrogen (NOX), polycyclic aromatic hydrocarbons (PAH), volatile organic compounds (VOC), hydrogen sulfide (H2S), acidic gases, trace metals, and particulate matter. At high levels many of these pollutants have been linked with short- and long-term illnesses, including upper respiratory irritation and a variety of cancers, and therefore were selected as the principal contaminants of concern and the focus of the literature review conducted by RAND.
For a period of about 8 months immediately after the ground war, US and international organizations conducted comprehensive air monitoring exercises (see Section IV). Ground level and airborne-based monitoring platforms collected numerous samples. The US Army Environmental Hygiene Agency conducted the most comprehensive monitoring program, which included well over 4,000 samples. The purpose of these monitoring activities was to characterize the contaminants of concern and, by measuring their relative concentrations in the atmosphere, lay the groundwork for assessing their likely short- and long-term impacts to human health and the environment.
In general, the monitoring results of the mean concentration of the pollutants were consistent among the various organizations involved in monitoring. Furthermore, the maximum observed concentrations of air contaminants, other than particulate matter, were similar to levels found in suburban locations in the US, and generally lower than those found in large urban areas. Overall, the RAND report notes that the monitoring data show that the concentrations of the pollutants present in the environment, particularly in areas where US troops and civilian personnel were located, fell below NIOSH, OSHA, or ACGIH recommended exposure limits for hazardous substances in the workplace.
It is important to note that these standards were used for comparison purposes only, as limits have not been established to protect US troops under exposure conditions experienced during deployment. That is, US ambient (NAAQS) and occupational (ACGIH) standards were established to protect the general US population and to provide protection in the workplace environment. Ambient standards were designed to protect populations that included the sick, the elderly, and the very young and would therefore provide a more conservative level of protection for US troops. Workplace standards, on the other hand, are based on 8-hour time-weighted-averages that take into consideration the fact that workers have recuperation time (off work) between exposure occurrences and that they are subjected to the exposure over a working lifetime (40 years). With respect to occupational standards there is a tradeoff. Troops on occasion were exposed longer than 8 hours per day, but the cumulative exposure was for several hours to a few weeks and not over a lifetime. Therefore it can be argued that neither of these standards are directly applicable to the exposures experienced by Gulf War veterans, and should only used as reference points when assessing exposures.
Table 9 presents the mean and maximum observed concentrations from the locations with the highest recorded levels of contaminants measured during the oil fires and compares them against US ambient and occupational exposure standards. The table was produced from data contained in Tables 2.8 and 2.11 of the RAND report.
Table 9: Mean and Maximum Concentrations of Pollutants of Concern, May - December 1991
|Pollutant||Mean Concentration||Maximum Concentration||NAAQS(1)||ACGIH TLVs(6)|
|Ozone||53.4 m g/m3||104.8 m g/m3||160 m g/m3(2)||100 m g/m3|
|Sulfur dioxide||23.8 m g/m3||92.5 m g/m3||80 m g/m3(3)||5,200 m g/m3|
|Nitrogen dioxide||58.5 m g/m3||86.1 m g/m3||100 m g/m3(3)||5,600 m g/m3|
|Acenaphthene||0.62 ng/m3||2.25 ng/m3||200,000 ng/m3|
|Benzo-anthracene||0.60 ng/m3||2.23 ng/m3||200,000 ng/m3|
|Biphenyl||7.2 ng/m3||19.07 ng/m3||200,000 ng/m3|
|Chrysene||0.48 ng/m3||2.25 ng/m3||200,000 ng/m3|
|Fluoranthene||1.41 ng/m3||2.23 ng/m3||200,000 ng/m3|
|Phenanthrene||0.48 ng/m3||1.84 ng/m3||200,000 ng/m3|
|Pyrene||0.65 ng/m3||3.5 ng/m3||200,000 ng/m3|
|Particulates||354 m g/m3||3,000 m g/m3||150 m g/m3(4)||300,000 m g/m3|
|Cadmium||0.003 m g/m3||0.0078 m g/m3||10 m g/m3|
|Chromium||0.027 m g/m3||0.0898 m g/m3||500 m g/m3|
|Nickel||0.052 m g/m3||0.2136 m g/m3||120 m g/m3|
|Lead||0.675 m g/m3||1.671 m g/m3||1.5 m g/m3(5)||50 m g/m3|
|Vanadium||0.028 m g/m3||0.0898 m g/m3||50 m g/m3|
|Zinc||0.068 m g/m3||0.193 m g/m3||500 m g/m3|
|Volatile Organic Compounds:|
|Benzene||7.82 m g/m3||13.1 m g/m3||1,600 m g/m3|
|Toluene||21.8 m g/m3||36.9 m g/m3||188,000 m g/m3|
|Ethyl-benzene||14.7 m g/m3||41.2 m g/m3||435,000 m g/m3|
|m, p - Xylene||40.5 m g/m3||116 m g/m3||435,000 m g/m3|
|o - Xylene||12.8 m g/m3||30.4 m g/m3||435,000 m g/m3|
|Source: The primary source of data contained in this table is US Army Environmental Hygiene Agency, Final Report - Kuwait Oil Fire Risk Assessment. No. 39-26-1192, February 1994, and the USEPA NAAQS and ACGIH standards referenced previously.|
From this table it can be seen that, with the exception of maximum observed ozone concentration, the mean and maximum reported concentrations of pollutants of concern were well below their respective ACGIH TLVs. Also from the table, it can be seen that contaminant levels, with the exception of particulates and the lead and sulfur dioxide maximum observed levels, were below US National Ambient Air Quality Standards (NAAQS) levels.
Particulate matter levels, although high, were considered to be within the range common to this area. As noted in Section IV, Kuwait has one of the highest background levels of particulate matter in the world. Based on historical data, levels are observed to range from 200 to 3,000 m g/m3. Comparison of measurements taken in the 1991 and 1994 (after the oil fires had been extinguished) show similar average values. Furthermore, a subset of the air samples collected in Kuwait and Saudi Arabia were analyzed to determine particle-type class and particle size distribution. Analyses of air samples taken in 1991, indicate that most of the PM10 is of sand origin and that in Kuwait, as noted in Section IV, only about 22 percent of the total PM10 mass was contributed by soot from the oil well fires.
C. Background Sources of Contaminants
In addition to the high levels of PM10 particulate matter, other background conditions in the region have had an impact on human health. For example, in the pre-war years, Kuwait embarked on a program to increase agricultural self-sufficiency and reverse the encroachment of the desert. This program called for desalinated seawater to be used for irrigation, leading to a "greening" of selected tracts of formerly barren desert land. An unintended consequence of this program was the introduction of high concentrations of pollen grains, fungi, molds, and spores appearing in the air over urban areas. These airborne contaminants have been directly related to an increase in the number of respiratory complaints in the indigenous population. For example, the prevalence of asthma and other allergy manifestations was 15.1% and 19.5% among adult males and females, respectively, in 1980. About 74% of these people were found to be allergic to pollens. Overall figures suggest a prevalence of asthma in Kuwait pre-invasion of around 18%. By comparison, the prevalence of asthma in the United States is 5-6% of the overall population.
Respiratory disease in Kuwait also follows a seasonal pattern, with higher hospital admissions during the cooler months despite a mean ambient temperature during this time period of around 20oC. Al-Shatti reports a positive correlation of +0.762 between the seasonal variation of the severity of complaints from asthma and allergy and the dust fall from sandstorms.
It should be noted that the prevalence of asthma in indigenous populations (i.e., those who have lived in a location their entire lives) does not imply that the same rates of asthma would be seen in US troops after a few weeks or months of exposure.
D. Possible Health Effects of Oil Fires
Health effects associated with each of the contaminants of concern are presented in the RAND report. The RAND report also notes that several health surveys were completed for US troops deployed to Kuwait.
A self-administered symptoms and medical history questionnaire was given to a group of soldiers prior to, and shortly after, their deployment to Kuwait. Results indicated a higher reported rate of short-term health problems while the troops were deployed to Kuwait. Symptoms included: eye irritation, burning eyes, shortness of breath, fatigue, skin rashes, and respiratory irritation. These short-term symptoms were associated with reported proximity to oil fires, and, after redeployment, their reported rate generally decreased over time.
Another self-administered questionnaire was completed by three groups of Marines, each of which had different degrees of exposure to the oil fires. Results indicated that the prevalence of short-term symptoms (e.g., wheezing, cough, and runny nose) was directly proportional to the time each spent in proximity to the oil fires.
Since the Gulf War, a study of self-reported symptoms in veterans from the State of Iowa has been conducted. Participants in the study were persons who listed Iowa as their home of record but who are not necessarily currently living in Iowa. Results of the study indicate that, compared with non-Gulf War veterans, Gulf War veterans reported a higher prevalence of adverse health effects. Also, there is a statistically significant 3.1% increase in the self-reported rate of asthma and bronchitis for Gulf War over non-Gulf War veterans.
E. Health Effects Associated with Short-term, Intense Exposures
The most severe exposures to US troops from the oil well fires occurred when they were in proximity to the damaged or burning wells. During these incidences, troops were subjected to short-term exposures where they were literally drenched in unburned oil and/or covered with fall-out (i.e., soot, smoke, and other by-products of combustion) from the oil well fires. These exposure incidents, while intense, were generally short in duration lasting from a few hours to several days. Reported short-term symptoms associated with these exposures included coughing, shortness of breath, eye and throat irritation, and black mucous from the nasal passage.
Dermal problems associated with exposure to crude oil do not appear to be a major concern. Macys, et al (1992) notes that while some populations may be sensitive to crude oil and exhibit mild irritations of the skin, crude oil in itself is not expected to pose an acute hazard due to skin contact. Volatile organic compounds (VOCs) contained in crude oil can pose a significant inhalation hazard, however. In very high concentrations they can be life threatening due to central nervous system depression. Monitoring conducted while the oil wells were burning, however, did not indicate that VOC concentrations were above levels of concern. [US EPA standard methods TO1, TO14, and TO17 were used for VOC sample collection.]
As noted in the RAND report, the health surveys conducted before and after the oil fires indicate increased symptoms and an association between prevalence of complaints and proximity to the oil fires. Health screening and clinical evaluations were not performed on US troops, however, and as a result, there are no data to indicate that those symptoms were indicators of disease or not. There is, however, a population of firefighters that experienced similar exposures and for which health-screening studies have been conducted. Therefore, some comparisons can be made.
Firefighters working in Kuwait to extinguish the fires also experienced short-term intense exposures. In general, these exposures were of similar or higher intensity and longer duration. Medical screening studies were conducted at the University of Texas on approximately 110 firefighters from Adair Enterprises, Boots & Coots, and Wild Well Control. Crews worked 10-12 hours per day and on average spent approximately 105 days in Kuwait fighting the fires. Personal protective equipment was limited to flame-retardant suits, hard hats, and safety shoes (i.e., no respiratory protection). Firefighters averaged 10 years of experience with some having over 30 years of experience fighting similar type fires in the US and abroad. Results of the health screening studies indicated that: 1) no objective evidence exists of any significant illness; 2) there were no reports of symptoms similar to those reported by Gulf War veterans; and 3) there were no reports of any illness with a delayed onset. [193, 194]
Various biological samples also were collected from troops or other personnel working in Kuwait while the fires burned. Poirier, et al (1994) report on blood level concentrations of polycyclic aromatic hydrocarbons (PAHs) in a group of 61 army soldiers deployed to the Persian Gulf in 1991. Blood samples were taken prior to deployment, during deployment, and post-deployment. The results of the blood analyses were compared with air and soil measurements of PAHs obtained from areas where the soldiers were working in Kuwait and with literature values for ambient PAH concentrations in the areas where the troops were prior to- and post-deployment. Results indicated that there was no evidence of increases in blood levels of PAH in soldiers stationed in Kuwait.
Etzel and Ashley, (1994) compared volatile organic compounds (VOCs) levels in the blood of firefighters, civilians in Kuwait City and a reference population in the US. The blood levels of VOCs in the firefighters were found to be higher than those in the US reference population, but approximately the same as individuals in Kuwait City (about 20 km from the oil fires). Small sample size and the short half-life of VOCs in the blood limit these data, but the results suggest that oil-well fire smoke did not significantly increase VOC exposures in troops in the Kuwait City area when most of the fires were active.
A number of firefighters were contacted to confirm the health screening results discussed above. In general, these firefighters are in good health and have not exhibited any of the symptoms commonly reported by veterans. In addition, they were not aware of other firefighters who may have experienced adverse health effects. And finally, they confirmed that they did not use respiratory protection during fire fighting operations. It should be noted, however, that firefighters are probably a self-limiting group in that any person susceptible to respiratory problems is not likely to continue to be employed in fire-fighting operations.
F. Ongoing and Planned Health Effects Investigations
In response to the general lack of information in the literature regarding the long-term health effects of particulate matter and oil fire smoke exposures a number of studies are underway or planned. Several of these studies are summarized below.
An Evaluation of Respiratory Function in Persian Gulf War Veterans. The objective of this study, being conducted by the Boston Environmental Hazards Center of the Boston VA Medical Center, is to assess respiratory status in relation to exposure to oil fire pollution in Gulf War Veterans and to evaluate the relationship between measures of pulmonary dysfunction and respiratory symptoms and exposure in an established and well-documented cohort. Pulmonary function data, blood laboratory test results, and general medical and pulmonary questionnaire data will be presented. The studys results will provide further knowledge about the effect of acute, high-level exposure to airborne particulate matter on respiratory health status. Results are expected in December 1998.
A Case-control Study of Asthma and Exposure to Oil Fire Smoke Among Gulf War Veterans. This study being conducted by the US Army Center for Health Promotion and Preventive Medicine (USACHPPM) is a work in progress and is being conducted to test the hypothesis that US troops exposed to oil fire smoke were at increased risk of receiving a diagnosis of asthma during medical examinations. The study utilizes estimates of exposure based on modeled smoke plumes, troop unit location information, and physician-diagnoses of asthma. Significant associations were observed for self-reported exposures to oil well fires and two model-based estimates of exposure: cumulative exposure and number of days that the total suspended particulates (TSP) concentration exceeded 150 m g/m3. Preliminary findings indicate that exposure to the smoke from oil well fires may be associated with an increased likelihood of asthma, and that this effect appears to be strongest among former smokers. Additional study is required before an etiologic association can be determined.
The Iowa Persian Gulf Study. The objective of this study was to assess the prevalence of self-reported symptoms and illnesses among military personnel from the state of Iowa deployed during the Gulf War, and to compare the prevalence of these conditions with the prevalence among military personnel on active duty not deployed to the Persian Gulf. The study methodology consisted of validated questions, validated questionnaires, and investigator-derived questions designed to assess relevant medical and psychiatric conditions. A study population of 28,968 subjects was selected based on the criteria that Iowa was listed as the home of record and there was military service at some time from August 2, 1990 through July 31, 1991. Preliminary results indicated that Gulf War veterans had a higher self-reported prevalence of medical and psychiatric conditions than military personnel who were not deployed. Planned follow-on studies involve health screening and medical examinations for a subset of the Iowa Gulf War veterans to validate the self-report of symptoms of asthma, depression, cognitive dysfunction, and multi-systemic conditions (i.e., chronic fatigue syndrome and fibromyalgia) and to assist in defining causal relationships between health outcomes and exposure incidents. In particular, 200 veterans will undergo medical exams and pulmonary function test to validate the veterans reports of asthma. Results are expected for the medical studies in October 1998.
Particulate Matter Health Effects Investigation and Exposure Assessment. Two separate but parallel studies are being conducted to assess the health impacts from exposure to respirable particulate matter. In the first study, The International Center for Environmental Health is conducting a literature search on what is known regarding the health effects associated with exposure to silica (the principal component of sand and particulate matter in the region). In the second study USACHPPM is conducting exposure modeling to estimate the levels of particulate matter to which US troops were exposed while deployed to the Persian Gulf region. Collectively these studies will allow for an overall estimate of risk associated with exposures to particulate matter. The health effects investigation is expected to be completed December 1998, and the exposure modeling study is expected in August 1999.
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