Health Study Activities Frequently Asked Questions (FAQs)

Mortality Study of Marines, Navy Personnel, and Civilian Workers – Cohort Study Update

1. What was the purpose of the study?

The purpose of this cohort study of Camp Lejeune Marines/Navy personnel and civilian workers was to determine if being stationed or employed at Camp Lejeune between 1975 and 1985 (Marines/Navy personnel) or between October 1972 and December 1985 (civilian workers), a portion of the period when the drinking water was contaminated, increased the risk of specific causes of death during the follow-up period between 1979 and 2018 compared to being stationed or employed at Camp Pendleton.

2. What was studied?

The Camp Lejeune Mortality Cohort Study was conducted of Marines and Navy personnel who, between 1975 and 1985, began service and were stationed at Camp Lejeune, North Carolina or Camp Pendleton, California and civilian workers employed at Camp Lejeune or Camp Pendleton between October 1972 and December 1985.

Camp Pendleton Marines/Navy personnel and civilian workers were chosen as the comparison groups in this study because the base's finished drinking water was not known to be contaminated prior to 1986. Additionally, Camp Pendleton's Marines/Navy personnel and civilian workers were similar to Camp Lejeune in terms of demographics, socioeconomic factors, training activities, personnel trained, and types of civilian employee occupations.

3. What were the features of the study?

Few studies have evaluated drinking water exposures to trichloroethylene (TCE), tetrachloroethylene (PCE), vinyl chloride, or benzene and the risk of specific causes of death. ATSDR previously conducted cohort Mortality Studies comparing Marines/Navy personnel and civilian workers stationed or employed at Camp Lejeune from 1975 to 1985 and 1972 to 1985, respectively, with similar cohorts over the same periods stationed or employed at USMC Base Camp Pendleton, California. The follow-up period for both of the previous Camp Lejeune mortality studies was between 1979 and 2008. The current cohort mortality study extends the follow-up period to 2018.

4. What were the conclusions and key results?

Drinking water at U.S. Marine Corps Base Camp Lejeune, North Carolina was contaminated with TCE and other industrial solvents from 1953 to 1985. Increased risk of several causes of death was observed among Marines and civilian workers exposed to contaminated drinking water at Camp Lejeune compared to personnel at Camp Pendleton, which is not known to have similar drinking water contamination.

• In Marines and Navy personnel, increased risk of causes of death was observed for kidney, esophageal, and female breast cancer.
• Among civilian workers, increased risk of causes of death was observed for chronic kidney disease, Parkinson disease, and female breast cancer.

5. What testing/treatment does ATSDR recommends?

This work is an update to the previous mortality studies published in 2014. It contributes to what is known about exposures to contaminated drinking water and health impacts. There are no specific medical tests that are recommended for these exposures. Instead, ATSDR recommends that individuals who think they may have been exposed to contaminated drinking water at Camp Lejeune monitor their health by having regular medical check-ups. We also encourage those persons to discuss this information with their physician, who can advise them on their personal health questions.

Cancer Incidence Study

1. What was the purpose of the cancer incidence study?

The cancer incidence study of Camp Lejeune Marines and Navy personnel, as well as civilian workers, was designed to investigate whether exposure to contaminated water at Camp Lejeune increased cancer risk.

2. Who was being studied?

Cancer incidence among Marines and Navy personnel, as well as civilian workers, who were stationed at or worked at Camp Lejeune between the mid-1970s and mid-1980s, (population size=154,821) was compared to Marines and Navy personnel and civilian workers at Camp Pendleton, California (population size=163,484) during the same period.

The Camp Lejeune and Camp Pendleton cohorts were similar in their demographics, socioeconomic status, training activities, and civilian employee occupations. However, in contrast to Camp Lejeune, Camp Pendleton drinking water was not known to be contaminated prior to 1986.

3. Why did this study only include Marines/Navy personnel who began service during 1975-1985 and workers employed at Camp Lejeune and Camp Pendleton during 1972-1985?

Drinking water contamination began in the 1950s. However, personnel data necessary to determine base location were not available prior to these years. The most heavily contaminated wells were shut down in 1985. Findings from this study also applied to people who were exposed to contaminated drinking water at Camp Lejeune before the study years.

4. What were the features of the story?

This is one of the largest studies of this type conducted in the United States, having used cancer registry data from all 50 states, the District of Columbia, Puerto Rico, the Pacific Islands, the U.S. Department of Defense, and the U.S. Department of Veterans Affairs.

5. What were the conclusions and key results?

Increased risk of several cancers was observed among Marines and civilian workers exposed to contaminated drinking water at Camp Lejeune compared to personnel at Camp Pendleton.

In Marines and Navy personnel, increased risk was found for some types of leukemia and lymphoma, as well as for cancers of the lung, breast, larynx, esophagus, thyroid, and soft tissues.

Among civilian workers, increased risk was observed for myeloid cancers and some cancers of the breast and lung.

6. What testing/treatment does ATSDR recommends?

ATSDR recommends that those who think they may be affected have regular medical check-ups to monitor their health. ATSDR also encourages those affected to discuss their exposure with their medical provider, who can advise them on their personal health questions.

Male Breast Cancer Study

1. What was the purpose of the study?

Some residents who lived at Camp Lejeune from the 1950s through 1985 were exposed to contaminated drinking water. The purpose of this study was to determine if Marines who were exposed to contaminated drinking water at Camp Lejeune were more likely to have male breast cancer.

2. Who was studied?

The study included 71 men with breast cancer (called "cases") and 373 men who had other cancers (called "controls"). ATSDR used the Department of Veteran's Affairs (VA) cancer registry to identify these cases and controls. ATSDR selected the controls from cancers that are not associated with solvent exposure; this included 270 men with skin cancer, 71 with mesothelioma, and 32 with bone cancer.

The VA's cancer registry maintains information from eligible veterans who were diagnosed with or treated for cancer at a VA clinic. Eligible study members were male Marines born before January 1, 1969, and diagnosed with cancer or treated for cancer at a VA medical facility from January 1, 1995, (the start of the VA's cancer registry) to May 5, 2013 (the latest date that complete medical records were available). Marines born after January 1, 1969, were not old enough to serve during the period of contamination at Camp Lejeune (i.e., they were younger than 17 years of age by the end of 1985 when the contamination ended).

3. Why did this study focus only on male breast cancer?

This study focused on male breast cancer because there is very limited information on the cause of breast cancer among men. The lack of scientific information on the disease is, in part, due to the uncommon occurrence of the disease among men. For every 1,000 cases of breast cancer in the United States about 7 occur among men. ATSDR's male breast cancer study aimd to further the scientific understanding of the disease by investigating whether exposure to volatile organic compounds (VOCs) in the drinking water at Camp Lejeune is associated with developing this uncommon disease.

4. Why does the study include only male Marines and not their dependents or civilian employees?

The study included only male Marines and not their dependents or civilian employees because the VA's cancer registry is not available for military dependents who lived at Camp Lejeune or civilian workers employed on the base. ATSDR conducted other health studies that include breast cancer in civilians who worked at Camp Lejeune during the time when the water was contaminated and breast cancer among females who were active-duty military members or civilian employees.

5. What did you find?

ATSDR's study results suggested possible associations between exposure to PCE, DCE, and vinyl chloride at Camp Lejeune and male breast cancer. These results took into account age at diagnosis, race, and service in Vietnam. For PCE, risk increased slightly with increasing levels of exposure.

Exposures to TCE, PCE, DCE, and vinyl chloride were also observed to possibly accelerate the onset of male breast cancer.

The study did not find evidence suggesting associations between male breast cancer and exposures to benzene.

The results of this study add to the scientific literature on the health effects of exposures to these chemicals in drinking water. However, these findings were based on small numbers of exposed cases.

ATSDR evaluated male breast cancer in a cancer incidence study that involved state cancer registries nationwide as well as federal cancer registries.

Adverse Birth Outcomes Study

1. What was the purpose of the study?

The purpose of this study was to determine if maternal exposures to contaminants in drinking water at Camp Lejeune were associated with preterm birth and fetal growth retardation.

This study is a reanalysis of a previous study that incorrectly categorized as "unexposed" some maternal exposures before June 1972 based on information available at the time. Additionally, the Agency for Toxic Substances and Disease Registry (ATSDR) recreated monthly estimates of past levels of drinking water contamination using computer models. These estimates were not available when the study was originally conducted.

2. Who was studied?

The study included live singleton births 28-47 weeks gestation weighing 500 grams or more that occurred between 1968 and 1985 to women who resided on base at time of delivery. We compared birth certificate data for Onslow County, NC, in which Camp Lejeune is located, with Camp Lejeune housing records. A total of 11,896 births met these criteria.

3. Which conditions were included in ATSDR's study?

The study included preterm birth and fetal growth retardation. Fetal growth retardation was measured by reduced mean birth weight (MBW), term low birth weight (TLBW), and small for gestational age (SGA). These birth outcomes have been previously found to increase the risk for negative health outcomes later in life.

• Preterm births were defined as births occurring at less than 37 weeks of gestation. We calculated gestational age using date of mother's last menstrual period from the birth certificate.
• TLBW was defined as full-term babies (37 weeks gestation or more) weighing less than 2,500 grams at birth.
• SGA births were defined as births weighing less than the 10th percentiles using sex- and race-specific weight by gestational week norms.
• For the MBW analysis, only full-term infants were included.

4. Why does this study examine only the period from 1968 to 1985?

The study is limited to children born between 1968 and 1985. These years were selected because computerized birth certificates became available in North Carolina in 1968 and the contaminated wells on base were shut down in 1985.

5. What did you find?

ATSDR's study results suggest associations between in utero exposure to PCE, TCE and benzene in Camp Lejeune drinking water and adverse birth outcomes.

The following effects were seen in births from 1968-1985 to women exposed to contaminated drinking water at Camp Lejeune. These findings also apply to women who gave birth before 1968 if they were exposed to similar levels of VOCs-contaminated drinking water.

• In utero exposure to PCE was associated with preterm birth.
  • For PCE and preterm birth, the strongest association was observed for exposure during the 2nd trimester.
• In utero exposure to TCE was associated with SGA, TLBW and reduced MBW.
  • The risk of TLBW increased with increasing levels of exposure to TCE during the 2nd trimester.
  • The finding for SGA is consistent with a previous study conducted in Woburn, MA.
• In utero exposure to benzene was associated with TLBW.
  • The risk of TLBW increased with increasing levels of exposure to benzene throughout the pregnancy.

6. How does this study help?

This study makes an important contribution to the scientific knowledge about the health effects of these chemicals. The information from this study, together with other information about the health effects of these chemicals, will play an important role in making decisions about setting acceptable levels of these contaminants in drinking water.

7. What does this study mean for the pregnant women and their children who were exposed to VOCs at Camp Lejeune?

This study attempts to answer some of the questions about the health effects of in utero drinking water exposures at Camp Lejeune. It also adds to the general knowledge about the health effects of these chemicals. The findings of this study might help the women and their children who were exposed to various contaminants in drinking water at Camp Lejeune better understand the association between their exposures and specific health outcomes.

Mortality Study of Civilian Employees Exposed to Contaminated Drinking Water at USMC Base Camp Lejeune: A Retrospective Cohort Study

1. What was the purpose of the study?

The purpose of the study was to determine whether potential exposures to the drinking water contaminants at Camp Lejeune are associated with increased risk of death from specific cancers and other chronic diseases among civilian workers employed at the base. The contaminants included trichloroethylene (TCE), tetrachloroethlylene (also known as perchloroethylene or PCE), benzene, and two contaminants formed when TCE or PCE degrade in groundwater: 1,2-dichloroethylene and vinyl chloride.

2. What was studied?

The study evaluated specific causes of death in 4,647 full-time workers who were employed at Camp Lejeune during 1973-1985. ATSDR also evaluated a comparison group of 4,690 full-time workers who were employed at Camp Pendleton during 1973-1985 and were not employed at Camp Lejeune during those years. The Camp Pendleton workers are a comparison group; that is, they were not exposed to contaminated drinking water.

Cause of death data from 1979-2008 were used to study the workers at Camp Lejeune and Camp Pendleton. Information on causes of death was obtained from the National Death Index (NDI) of the National Center for Health Statistics. The study included all underlying causes of death that other studies have shown to be associated with one or more of the chemicals found in the drinking water at Camp Lejeune. Causes of death were selected based on literature reviews conducted by the U.S. Environmental Protection Agency (EPA), the National Toxicology Program (NTP), the International Agency for Research on Cancer (IARC), and Agency for Toxic Substance and Disease Registry (ATSDR).

The study looked at data for these causes of death:

• Amyotrophic lateral sclerosis (ALS)
• Cancers of the bladder, brain, cervix, colon, esophagus, female breast, kidney, larynx, liver, lung, oral cavity, pancreas, prostate, rectum, and soft tissue
• Hematopoietic cancers
  • Hodgkin's Lymphoma
  • Leukemias
  • Multiple myeloma
  • Non-Hodgkin's lymphoma
• Non-cancerous kidney diseases
• Non-cancerous liver diseases
• Multiple sclerosis
• Parkinson's disease

Also included in the study were three causes of death known to be caused by cigarette smoking but not known to be associated with the drinking water contaminants: cardiovascular disease, chronic obstructive pulmonary disease (COPD), and stomach cancer. These causes of death were included to assess the possible impact of smoking on the findings because information on smoking status was not available for study subjects.

3. Why does this study include only workers employed at Camp Lejeune and Camp Pendleton during 1973-1985?

The timeframe includes the period when exposure occurred and for which data are available. The period ended with the closure of the most heavily contaminated wells. Specifically, the study evaluates civilian workers at Camp Lejeune and Camp Pendleton who were employed at either base any time between the second quarter of 1973 and the end of 1985. Continuous quarterly information on DOD employment from the Defense Manpower Data Center began with the second quarter of 1973. The most heavily contaminated wells at Camp Lejeune were shut down in 1985.

4. Why was Camp Pendleton used for the comparison group?

To determine whether mortality rates were higher for Camp Lejeune civilian workers, ATSDR wanted to compare their mortality rates with those of an appropriate comparison population. The Camp Lejeune civilian worker mortality rates could have been compared with the general U.S. population. However, worker populations usually have lower mortality rates than the general U.S. population because of the "healthy worker effect." That is, healthy individuals are more likely to be employed and remain employed, while the general U.S. population includes people who are not healthy enough to be employed. To avoid the problem of the healthy worker effect, an appropriate comparison population for a worker cohort is another worker cohort. Camp Pendleton civilian workers have similar occupations as the Camp Lejeune civilian workers, but they were not known to be exposed to contaminated drinking water.

5. Why did ATSDR include smoking-related conditions?

The study included three causes of death known to be caused by cigarette smoking but not known to be associated with exposure to volatile organic compounds: stomach cancer, cardiovascular disease, and chronic obstructive pulmonary disease (COPD). These causes of death were included to assess the possible impact of smoking on the findings. No information was available on smoking status of the study subjects.

6. What did you find?

During 1979-2008, there were 654 deaths in the Camp Lejeune group of civilian workers and 869 deaths in the Camp Pendleton group. The median ages in 2008 for the Camp Lejeune and Camp Pendleton cohorts were 58 years and 60 years, respectively.

Compared with the Camp Pendleton workers, the Camp Lejeune workers had higher mortality rates for the following causes of death:

• Cancers of the female breast, kidney, lung, oral cavity, prostate, and rectum
• Kidney diseases
• Leukemias
• Multiple myeloma
• Parkinson's disease

The higher rates of cancers of the kidney, prostate and rectum, leukemias, and Parkinson's disease were mainly among the Camp Lejeune civilian workers with higher cumulative exposures to the contaminants.

When civilian workers with higher exposures at Camp Lejeune were compared to Camp Lejeune workers with lower exposures, higher cumulative exposures to the contaminants were associated with increased risks for cancers of the kidney, esophagus, prostate, and rectum, leukemias, and Parkinson's disease.

The findings for the smoking-related causes of death, such as stomach cancer, cardiovascular disease, and chronic obstructive pulmonary disease suggested that smoking would only slightly increase the risk of any association between cause of death and exposure to the drinking water contaminants at Camp Lejeune.

7. Did this study provide evidence of causation?

This study makes an important contribution to the scientific literature by providing additional information about the health effects of exposure to volatile organic compounds in drinking water. It does not, however, provide definitive evidence that exposure to the contaminants caused any specific health outcome because of the following limitations:

Small numbers of specific causes of death; the resulting wide confidence intervals indicate considerable uncertainty about the actual risk (it could be higher or lower).

Short exposure durations likely reduced the magnitude of the effects.

Exposure misclassification:

• Uncertainty about the drinking water use of civilian workers at Camp Lejeune.
• Uncertainty about workplace locations (e.g., during the workday, aworker may have been assigned to multiple locations at the base).
• Disease misclassification bias (a worker may have been misdiagnosed with a disease or may have had a disease that was not diagnosed).
• Lack of information on other exposures or risk factors.

Evaluation of Mortality Among Marines and Navy Personnel Exposed to Contaminated Drinking Water at USMC Base Camp Lejeune: A Retrospective Cohort Study

1. What was the purpose of the study?

The purpose of this study was to determine whether residential exposures of Marine and Naval personnel to contaminated drinking water at Camp Lejeune increased risk of mortality from cancers and other chronic diseases.

2. What was studied?

The study evaluated specific causes of death in 154,932 Marines and Navy personnel who began service during 1975-19851 and were stationed at Camp Lejeune anytime during this period. We also evaluated a comparison group of 154,969 Marines and Navy personnel from Camp Pendleton. The Camp Pendleton group was not exposed to contaminated drinking water but was otherwise similar to the Camp Lejeune group.

Cause of death data from 1979-2008 was used to study the Camp Lejeune and Camp Pendleton cohorts. Information on causes of death was obtained from the National Center for Health Statistics National Death Index (NDI). The study included all underlying causes of death that other studies have shown associations with one or more of the chemicals found in the drinking water at Camp Lejeune. Causes of death were selected based on literature reviews conducted by the U.S. Environmental Protection Agency (EPA), the National Toxicology Program (NTP), the International Agency for Research on Cancer (IARC), and ATSDR.

The causes of death studied include:

• Amyotrophic lateral sclerosis (ALS)
• Cancers of the bladder, brain, cervix, colon, esophagus, female breast, kidney, larynx, liver, lung, oral cavity, pancreas, prostate, rectum, and soft tissue
• Hematopoietic cancers
  • Hodgkin's Lymphoma
  • Leukemias
  • Multiple sclerosis
  • Non-Hodgkin's lymphoma
• Non-cancerous kidney diseases
• Non-cancerous liver diseases
• Multiple sclerosis

Also included in the study were three causes of death that are known to be caused by cigarette smoking but are not known to be associated with the drinking water contaminants: stomach cancer, cardiovascular disease, and chronic obstructive pulmonary disease (COPD). These causes of death were included to assess the possible impact of smoking on the findings because we did not have information on smoking status for study subjects.

3. Why did this study include only Marines and Navy personnel who began service during 1975-1985?

Unit information was needed to determine where the Marines or Navy personnel were stationed. ATSDR could only include Marines and Navy personnel who began service during 1975-1985 and who were stationed at either Camp Lejeune or Camp Pendleton during this timeframe because unit information first became available from the Defense Manpower Data Center (DMDC) personnel database in the second quarter of 1975. Also, the most heavily contaminated wells were shut down in 1985.

4. Why was Camp Pendleton used as the comparison cohort (population)?

The study included a comparison population from Camp Pendleton that was similar to the Camp Lejeune cohort on risk factors such as military training, occupations, and smoking. Camp Pendleton did not have a contaminated drinking water supply.

Residential cumulative exposure to each contaminant was based on results from the water modeling and the location and duration of residence.

5. What did you find?

Compared to Camp Pendleton, the Camp Lejeune group had higher mortality rates for the following causes of death:

• Cancers of the cervix, esophagus, kidney, liver, lung, pancreas, prostate, rectum, and soft tissue
• Hodgkin's lymphoma
• Leukemias
• Multiple myeloma
• Multiple sclerosis

The higher rates for kidney cancer, cervical cancer, Hodgkin's lymphoma, leukemias, multiple myeloma, and lung cancer were mainly among those with higher cumulative exposures to the contaminants. However, the precision of the estimated rates of many of these conditions was low.

The findings for the smoking-related causes of death such as stomach cancer, cardiovascular disease, and (COPD) suggested that smoking would have only a slight impact on the associations between causes of death and exposure to the drinking water contaminants at Camp Lejeune.

6. Does this study provide evidence of causation?

The study found increased risk of death in the Camp Lejeune cohort for several causes including cancers of the cervix, esophagus, kidney, and liver, Hodgkin's lymphoma, and multiple myeloma. This study makes an important contribution to the body of evidence about harm caused by these chemicals. However, due to its limitations it did not provide definitive evidence for causality, nor can it answer the question whether an individual has been affected by these exposures at Camp Lejeune.

Birth Defects and Childhood Cancers Study

1. What progress has ATSDR made on its study of contaminated drinking water at Camp Lejeune and specific birth defects and childhood cancers?

ATSDR has finalized a study on specific birth defects and childhood cancers. The study includes children born from 1968 through 1985 to mothers who for some time during their pregnancy lived at Camp Lejeune. The study looked at whether children whose mothers were exposed to contaminated drinking water while they were pregnant at Camp Lejeune were more likely to have specific birth defects. The study also looked at whether children exposed to contaminated drinking water in utero or during their first year of life were more likely to have specific childhood cancers. Parents of the children were interviewed in spring/summer 2005 about where they lived at Camp Lejeune from 1968 through 1985, their medical histories, and their personal habits.

2. Why did this study examine only the period from 1968 to 1985?

The study only included children born between 1968 and 1985 because computerized birth certificates in North Carolina became available in 1968 and the heavily contaminated wells on base were shut down in 1985.

3. Which conditions were included in ATSDR's study?

The study included:

• neural tube defects (NTD), consisting of anencephaly (absence of a major portion of the brain) and spina bifida,
• cleft lip and cleft palate,
• and childhood leukemia and non-Hodgkin lymphoma.

4. Why does the study focus only on neural tube defects, oral clefts, childhood leukemia, and childhood non-Hodgkin lymphoma?

ATSDR chose to study these diseases because studies conducted elsewhere suggested that exposures to the chemicals in the Camp Lejeune drinking water might cause these health effects. ATSDR tried to study other birth defects and childhood cancers, but not enough cases were identified during the 1999-2002 survey.

5. How did ATSDR identify the cases of NTDs, cleft lip and palate, and childhood leukemia and non-Hodgkin lymphoma?

There was no cancer or birth defect registry in North Carolina during 1968-1985, so ATSDR had to conduct a phone survey of parents who lived on base during this period to identify cases of these diseases. ATSDR then confirmed the diagnoses of these diseases by obtaining medical records.

6. How did the drinking water at Camp Lejeune get contaminated?

The water system serving the Tarawa Terrace housing area was contaminated by PCE dumped into the environment by an off-base dry cleaner. The Hadnot Point water system serving the main portion of the base ("mainside") was contaminated by TCE, PCE and benzene from several sources on base including

• leaking underground storage tanks,
• industrial area spills,
• and leaching from a toxic waste dump.

7. Why did it take 8 years after ATSDR completed data collection to analyze and report the findings of this study?

Study researchers had to wait until ATSDR's water modeling was completed to find out the levels of contaminants in the water systems during 1968-1985. Sample data showing the levels of specific contaminants in the water systems were only available starting in 1982. Therefore, modeling was needed to estimate contaminant levels prior to 1982. We also needed to model the contaminant levels from 1982 onward because of insufficient sampling data. ATSDR completed the study soon after the modeling results were available.

8. What did you find?

Study findings suggested that mothers who had first trimester exposures to drinking water contaminated with TCE at Camp Lejeune were more likely to have a child with a neural tube defect compared with unexposed mothers. The higher the mother's exposure to TCE, the higher the likelihood that the child would have a neural tube defect. This finding is consistent with a previous study conducted in New Jersey (Bove FJ, et al. Public drinking water contamination and birth outcomes. Am J Epidemiol 1995, 141:850-862).

Study findings also suggested that mothers who had first trimester exposures to drinking water contaminated with benzene were more likely to have a child with a neural tube defect compared with unexposed mothers. However, we could not look at whether higher benzene exposures increased the likelihood of having a child with a neural tube defect because of small numbers of exposed cases.

Mothers with first trimester exposures to PCE, vinyl chloride, or DCE were more likely to have a child with leukemia or non-Hodgkin lymphoma compared with unexposed mothers. However, these findings are weaker than the findings for neural tube defects because higher exposures did not increase the likelihood that the child would have these cancers.

9. What is different about this study?

ATSDR's study is unique because we were able to model the average monthly levels of the contaminants in the drinking water. We used these data to find out whether mothers exposed to these contaminants during pregnancy were more likely to have a child with a specific birth defect or childhood cancer. This effort included assessment of contaminant levels from the source to the residences averaged on a monthly basis.

There is little information in the scientific literature on whether maternal drinking water exposures to the contaminants at Camp Lejeune are linked to birth defects and childhood cancers. Very few studies have focused on the health effects of maternal drinking water exposures. Most studies in the literature have focused on the health effects of workplace exposures to mothers.

ATSDR's water modeling approach is unique for its complexity. We needed to determine how the chemicals moved from the locations where they entered the environment through groundwater to drinking water supply wells and then into the distribution system. The modeling estimated monthly mean concentrations for specific VOCs—PCE, TCE, trans-1,2-DCE, vinyl chloride, and benzene. We needed monthly estimates so that we could estimate exposures during specific pregnancy trimesters.

10. How does this study help?

This study makes an important contribution to the scientific knowledge about the health effects of these chemicals. Information from this study, along with other information about the health effects of these chemicals, will help with policy and regulatory decisions about regulating these contaminants in drinking water.

11. What does this study mean for those pregnant women and their children who were exposed to VOCs at Camp Lejeune?

For mothers and their children who were exposed to the contaminated drinking water at Camp Lejeune, this study may add to their knowledge and understanding about the health effects of these exposures.

12. Why does the study use the word "suggest" instead of a stronger word?

It is hard to be definitive with one study, especially when that study has small numbers of exposed cases.

13. Why didn't you see an association between benzene and childhood cancer?

We did not see an association between benzene and childhood cancers in this study, but that does not mean that benzene does not cause childhood cancer. It only means that we did not find evidence in this study. There is a gap in the scientific literature about whether benzene is associated with childhood hematopoietic cancers.

Reasons why we didn't see an association may include:

• The levels of benzene were too low
• Biases, such as exposure misclassification, may have influenced the results
• There were small numbers of exposed benzene cases
• There may not be an association between benzene and childhood hematopoietic cancers

14. Does this study provide evidence of causality?

This study provides some evidence; however, the evidence is not strong for the following reasons:

• Small numbers of exposed cases make it difficult to evaluate exposure-response trends.
• Small numbers of exposed cases result in wide confidence intervals, so there is considerable uncertainty about the actual risk (it could be much higher or much lower).
• This study, like other environmental and occupational studies, is subject to errors in determining people's exposures and other possible biases which add uncertainty to the results.
• Because there are so few studies in the literature, it is not possible to be definitive about causality. However, once more studies are conducted that find similar results as this study, the evidence may be stronger for causality.

Morbidity Study of Former Marines, Employees, and Dependents Potentially Exposed to Contaminated Drinking Water at USMC Base Camp Lejeune: A Summary of ATSDR's Study Design and Results

1. Why did you develop the health survey?

On January 28, 2008, President Bush signed the 2008 National Defense Authorization Act. This required ATSDR to develop a health survey of persons possibly exposed to contaminated drinking water at Camp Lejeune.

2. Who was eligible for the survey?

Anyone who lived or worked at Camp Lejeune during the period of drinking water contamination was eligible for the survey. ATSDR couldn't identify all of these people from available records, so we sent the survey to the people we could identify.

People who received the survey included:

• former active-duty marines and sailors who were stationed at Camp Lejeune anytime between April 1975 and December 1985
• civilian employees who worked at the base anytime between October 1972 and December 1985

• People who took part in ATSDR's 1999-2002 survey
• a sample of former active duty and civilian workers from Camp Pendleton
• people who requested a health survey by registering with the United States Marine Corps before June 30, 2011

3. Why did you survey former active duty and civilian workers from Camp Pendleton?

Active duty and civilians who worked at Camp Pendleton and Camp Lejeune are similar except for their exposures to chemicals in drinking water. The information from those who lived at Camp Pendleton allows us to compare the health experiences between these two groups. This will help us determine if contaminated drinking water at Camp Lejeune affected people's health.

4. What conditions did the health survey ask about?

The health survey asked questions about more than twenty different cancers and other diseases. People also had space to report other diseases not mentioned in the survey.

5. When was the survey sent?

The surveys were mailed from June 2011 through June 2012.

6. Why didn't I get a survey?

You may not have received a survey because you are not part of one of the groups included in the health survey. The following groups were included in the health survey:

• former active-duty marines and sailors who were stationed at Camp Lejeune anytime during April 1975 and December 1985
• civilian employees who worked at the base anytime during October 1972 to December 1985
• people who took part in ATSDR's 1999-2002 survey
• a sample of former active duty and civilian workers from Camp Pendleton
• people who requested a health survey by registering with the USMC by June 30, 2011

Even if you did not receive a survey, if you lived or worked at one of the bases during this time, the results will apply to you.

7. What did you find?

This survey showed that contaminated drinking water at Camp Lejeune was linked to increased risk for bladder cancer, kidney cancer, and kidney disease.

• Exposure to both TCE and PCE was associated with an increased risk for kidney cancer in both Marines and civilian employees
• Exposure to both TCE and PCE was associated with increased risk for bladder cancer and kidney disease in civilian employees
• Exposure to PCE was associated with increased risk for bladder cancer and kidney disease in Marines

Risk increased with increasing levels of exposure to the contaminants for kidney cancer (TCE and PCE in Marines and TCE/PCE in civilian employees) and kidney disease (PCE in Marines and TCE/PCE in civilian employees). These results are consistent with results found in previous studies.

Public Health Assessment (PHA)

1. Why did the 1997 PHA not mention benzene was present in well 602?

The 1997 PHA does mention benzene in Appendix B (page B-2-4). It does not mention or discuss benzene in the main body of the PHA because we assumed, incorrectly at the time, that well # 602 was not used to supply contaminated drinking water to residents of Camp Lejeune.

2. Why did ATSDR remove the 1997 PHA from the ATSDR Camp Lejeune website?

In the time since the 1997 PHA was published, additional information emerged related to exposures to volatile organic compounds in drinking water at Camp Lejeune. Due in part to ATSDR's ongoing extensive water modeling and exposure reconstruction study, we learned that communities serviced by the Holcomb Boulevard distribution system were exposed to contaminated water for a longer period than we knew in 1997. Also, at the Camp Lejeune site, benzene was present in one drinking-water supply well in the Hadnot Point drinking water system. That well was shut down sometime prior to 1985. This information should have been included in the PHA but was not. The PHA should have mentioned the contamination and stated that the extent of exposure to benzene from that well was unknown.

3. When will the revised PHA be available?

"The 1997 PHA was removed from the ATSDR website in 2009 and was replaced with an updated PHA in January 2017. This updated 2017 PHA evaluates exposures to volatile organic compounds (VOCs) based on new analyses and studies, particularly the findings from ATSDR's historical reconstruction modeling efforts, and evaluates more recent exposure to lead in drinking water based on sampling data collected by the United States Marine Corps at Camp Lejeune.