RFP STATEMENT OF WORK
The intent of the RFP is twofold, to:
-
Develop and document a detailed methodology for retrospectively characterizing the exposure of Vietnam veterans to the major herbicides used by the military in Vietnam: 2,4-D; 2,4,5-T; cacodylic acid; picloram; and the trace contaminants TCDD and its congeners. The proposal should address how exposure to this array of chemicals will be evaluated. However, the ability to separately identify or quantify exposures to each of these substances is not necessarily a requirement for a successful proposal. The exposure methodology proposed must be applicable to specific types of epidemiologic investigations that could be conducted at a future date under a separate contract or subcontract.
-
Demonstrate the feasibility and appropriateness of the proposed methodology in sufficient detail to permit the assessment of its potential for use in the conduct of epidemiologic studies.
The final product of the research funded under the RFP should include a written, detailed description of the exposure assessment method proposed, the level of exposure discrimination that can be produced, and the results of the validation studies for that method.
The RFP is not intended as a solicitation for an epidemiologic study of health effects or other outcomes potentially associated with herbicide exposure. Such studies may be solicited in the future, but the current request for proposals is restricted to development and testing of an exposure assessment approach for Vietnam veterans that is appropriate for use in such future epidemiologic studies.
A more detailed description of the activities to be conducted by the successful respondent(s) is provided below.
SUPPLEMENTAL INFORMATION
The focus of the RFP is on exposure assessment approaches for use in studies of Vietnam veterans. Previous IOM reports have cataloged and summarized the available information on the health outcomes associated with exposure to herbicides or the contaminant dioxin. The conclusions in these reports are based largely on studies of nonveteran populations (i.e., occupational cohorts or communities exposed after industrial accidents). A full understanding of the specific risks for Vietnam veterans requires studies of the veterans themselves, which in turn require a better understanding of the herbicide exposures encountered by various military groups during the Vietnam War. The RFP does not preclude the use of exposure assessment models or data developed or validated on non-Vietnam veteran populations, provided they are
used to develop a model of exposure assessment for Vietnam veterans under the subcontract.
The RFP is intended to address assessment of all exposure to herbicides used during the Vietnam War. These herbicides are listed in Table 1. Several different herbicides and herbicide mixtures were used in varying combinations by the United States during the conduct of the war. Furthermore, some of these herbicides were contaminated with dioxins (TCDD and its congeners) at varying levels. Each of these chemicals has characteristics (e.g., half life and solubility) that will affect a person's dose at a given level of exposure. Because these chemicals also have distinctive toxicities, the proposal should acknowledge these complexities, not focus solely on TCDD. The proposal should address how exposure to this array of chemicals will be evaluated.
TABLE 1 Major Herbicides Used in Operation Ranch Hand: 1962–1971
Herbicide Code Name |
Formulation |
Purpose |
No. of Gallons Sprayed |
Period of Use |
Purple |
2,4-D; 2,4,5-T |
General defoliation |
145,000 |
1962–1964 |
Blue (Phytar 560-G) |
Cacodylic acid |
Rapid defoliation, grassy plant control, and rice destruction |
1,124,307 |
1962–1971 |
Pink |
2,4,5-T |
Defoliation |
122,792 |
1962–1964 |
Green |
2,4,5-T |
Crop destruction |
8,208 |
1962–1964 |
Orange, Orange II |
2,4-D; 2,4,5-T |
General defoliation |
11,261,429 |
1965–1970 |
White (Tordon 101) |
2,4-D; picloram |
Forest defoliation, long-term control |
5,246,502 |
1965–1971 |
SOURCES: MRI, 1967; NAS, 1974; and Young et al., 1988. |
A paper included as the Appendix to this report is provided as background for potential respondents. This paper, entitled "The Assessment of Exposure to Herbicides among Vietnam Veterans: A Review and Recommendations for Future Studies," provides an overview of the U.S. military's use of herbicides during the Vietnam War, a review of prior exposure assessment research efforts, and a discussion of potential approaches to herbicide exposure assessment research. This paper was not written by the Committee on the Assessment of Wartime Exposure to Herbicides in Vietnam or any of its members, and it should not be viewed as instruction from the committee regarding the form or content of proposals. Instead, it should be treated as a summary of the information regarding exposure assessment contained in the IOM reports Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam and Veterans and Agent Orange: Update 1996.