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It is bittersweet that the cancer study results of the Agency for Toxic Substances and Disease Registry (ATSDR) confirm employees and service members of Camp Lejeune experience higher rates of disease. While no one wants their worst fears validated, the publication of this study provides another route to justice for so many suffering from the effects of exposure to contaminated water.
The ATSDR is no stranger to the history of Camp Lejeune water contamination and has performed decades of studies on how chemical contaminants have affected military members and civilians stationed or employed at Camp Lejeune. The latest ATSDR Cancer Incidence Study is a significant breakthrough, offering evidence of increased hazard ratios (HRs) for individuals exposed to contaminated water at the military base.
The Significance of ATSDR Cancer Incidence Study for Camp Lejeune
Few studies exist that evaluate drinking water contaminated with Tetrachloroethylene (PCE), Trichloroethylene (TCE), Vinyl Chloride, Benzene, and other chemicals found in the wells at Camp Lejeune. The ATSDR Cancer Incidence Study further confirms the connection between Camp Lejeune’s contaminated water and cancer. This cancer study will be influential in finally getting Camp Lejeune civilians, veterans, and their families the finality they deserve.
Purpose of the Camp Lejeune Marines Cohort Cancer Study
While other epidemiological studies have examined the relationship between drinking water contaminants and cancer, the ATSDR Cancer Incidence Study focused on determining whether the site of the exposure, Camp Lejeune, led to higher hazard ratios, as compared to Camp Pendleton.
Pathways to Exposure at Camp Lejeune
The ATSDR Marines/Navy Cohort Study compared cancer incidence rates for those working or living at Camp Lejeune between 1975 and 1985 (Navy/Marine personnel) and between 1972 and 1985 (civilians) to similar cohorts stationed or employed at Camp Pendleton over the same periods. The drinking water exposures at Camp Lejeune included three routes: ingestion, inhalation, and dermal, making the cancer study results applicable to all individuals living or working at Camp Lejeune during the timeframes listed above.
Because Camp Pendleton was not known to have contaminated drinking water before 1986, research can tie cancer incidence to the location of the cohorts, rather than to other factors. Camp Pendleton’s cohorts were similar to Camp Lejeune’s in terms of demographics, socioeconomic factors, training activities, and types of civilian employee jobs, so it is fair to believe similar lifestyle and occupational factors affected both groups, leaving the base to be the differentiator.
ATSDR Cancer Incidence Study Subjects and Controls
Cohorts for the cancer study included 211,023 Navy/Marine personnel at Camp Lejeune and 224,419 at Camp Pendleton, who were known to be alive as of January 1, 1996. A subgroup of service members was pulled from this larger pool as the focus of the Camp Lejeune Marines/Navy Cohort Cancer Study. The timing (start dates between 1975 and 1985) is a period when adequate base records were available and would omit anyone who may have served at Camp Lejeune before serving at Camp Pendleton. This subgroup consisted of 154,821 individuals from Camp Lejeune and 163,484 individuals from Camp Pendleton, who were known to be alive as of January 1, 1996.
The start date of the cancer study results follow-up was January 1, 1996, because all cancer registries were operating by then, and December 31, 2017, was the chosen end date. The study gathered information on individuals diagnosed with invasive cancers and in-situ bladder cancer from that period.
Data collection was a major strength of the ATSDR Cancer Incidence Study, as records were gathered from every state and territorial cancer registry, the D.C. registry, the VA cancer registry, and the Department of Defense cancer registry. Unlike the National Death Index, there is no central cancer incidence registry in the U.S. Each registry where Marine/Navy personnel resided after service or employment had to be matched back to the database of workers and residents. Survival methods were then used to calculate hazard ratios (HRs) comparing cancer incidence between the Camp Lejeune and Camp Pendleton cohorts.
Contaminated Drinking Water Study Results
Drinking water at Camp Lejeune was supplied by eight treatment plants, each serving a different area of the base. Water samples collected between 1980 and 1985 at Camp Lejeune revealed industrial solvents in the drinking water supplied by two of the base’s eight treatment plants. Because drinking water data on volatile organic compounds is not available for all years of the study, ATSDR conducted historical reconstruction modeling to estimate the contaminant levels in the base’s water treatment distribution systems.
The ATSDR Cancer Incidence Study provides data for HP (Hadnot Point treatment plant), which serviced barracks, workplaces, training, and dining facilities, and TT (Tarawa Terrace treatment plant), which serviced family housing. While contamination levels in each system fluctuated depending on the wells in use and other factors, comparing the study results to the Environmental Protection Agency Maximum Contaminant Level (MCL) for the chemicals as we’ve done below paints a clear picture:
- Trichloroethylene (TCE): Monthly median concentrations in the HP distribution system measured 366 μg/L, exceeding the EPA MCL of 5 µg/L.
- Perchloroethylene (PCE): Monthly median concentrations in the TT distribution system measured 85 μg/L and 15 μg/L in the HP distribution system; both exceeded the EPA MCL of 5 µg/L.
- Vinyl Chloride: Monthly median concentrations in the HP distribution system measured 22 μg/L, exceeding the EPA MCL of 2 µg/L for Vinyl Chloride.
- Benzene: Not estimated in this analysis, but Benzene was detected in 1985 and measured 2,500 µg/L on November 19th and 38 µg/L on December 10th; the EPA MCL for Benzene is 5 µg/L.
The EPA classifies TCE as a human carcinogen; PCE is classified as a “likely human carcinogen,” and Benzene and Vinyl Chloride are known human carcinogens.
Evaluating Cancer Types in ATSDR Cohort Study
A major strength of the ATSDR Cancer Incidence Study was the evaluation of both cancer types and histological subtypes. Previous drinking water studies have focused on cancer overall rather than detailing various subtypes. The ATSDR study’s analysis offered a more nuanced understanding of how exposure relates to subtypes of certain cancers, including lymphoma, lung, and head and neck cancers.
This cancer incidence study accounted for specific variables — for example smoking and other lifestyle choices — and found them not to be influential in the results. Interpreting the results reflects these four considerations factored into the study:
- The magnitude of the adjusted HR estimate (a 20% or greater increase in incidence)
- The precision of the estimate (using a 95% confidence interval)
- The quantitative impacts of unmeasured potential confounders (misclassification of exposure due to smoking, alcohol use, and other lifestyle factors)
- Supporting information from the scientific community on TCE, PCE, Vinyl Chloride, and Benzene
This Camp Lejeune Marines/Navy Cohort Cancer Study is breakthrough research that confirms what we’ve long suspected—those stationed and working at Camp Lejeune have experienced a lifetime of hardships due to diseases related to contaminated water.