320,000 soldiers to Vietnam, the second largest force after the United States. South Korea has indicated a new willingness to address the Agent Orange issue by reviewing recommendations from its Veterans Office to cover health costs of alleged Agent Orange victims and possibly file legal action against U.S. chemical manufacturers (New York Times, 1992b).

A number of components of the National Research Council (NRC) and the Institute of Medicine (IOM) have studied the effects of Agent Orange and other herbicide use in Vietnam. Several groups developed conclusions directly related to the issues that are currently being examined by the IOM.

The NRC first became involved in the evaluation and understanding of the health effects of exposure to Agent Orange in 1970. As mentioned above, Public Law 91-441 of 1970 directed the Department of Defense to contract with the NAS for a study of the ecological and physiological effects of the military use of herbicides in Vietnam. A committee, organized through the Assembly of Life Sciences (ALS) of the National Research Council, developed an inventory of the areas sprayed by herbicides, based on DOD log books on herbicide missions. These data were transferred to data tapes (the so-called HERBS tapes) and provide information on 6,542 spray missions that occurred from August 1965 to February 1971, using a total of 17.6 million gallons of herbicide, of which approximately 11.3 million gallons and 4,109 missions involved Agent Orange. The committee reviewed the effects on various types of vegetation, studied the persistence of herbicides in the soil, and attempted to identify effects of the herbicides on resident populations believed to have been exposed. Its investigation determined that mangrove forests were particularly vulnerable to herbicide spraying, as were standing food crops. The extent of damage to the inland forest was more difficult to estimate since, for security reasons, the committee had to rely on aerial photographs in estimating the extent of damage (NAS, 1974).

The committee was unable to determine the direct effects of herbicides on human health. Individual case reports of adverse health effects could not be substantiated, although one component of the report published eight years later (Kunstadter, 1982) reviewed hospital records on births and birth defects in Vietnam. This report remained inconclusive as to the relationship between maternal exposure to herbicides and the incidence of birth defects.

In 1979, the Air Force requested that NAS review a protocol for an investigation of the health effects of Agent Orange exposure on Ranch Hand personnel. A panel, organized by the ALS, suggested that the number of Air Force personnel exposed to Agent Orange was too small to have sufficient statistical power to detect meaningful health effects in the proposed time

Front Matter (R1-R20)

1 Executive Summary (1-22)

2 History of the Controversy Over the Use of Herbicides (23-73)

3 The U.S. Military and the Herbicide Program in Vietnam (74-110)

4 Toxicology (111-220)

5 Methodologic Considerations in Evaluating the Evidence (221-249)

6 Exposure Assessment (250-299)

7 Epidemiologic Studies (300-432)

8 Cancer (433-590)

9 Reproductive Effects (591-639)

10 Neurobehavioral Effects (640-671)

11 Other Health Effects (672-720)

12 Research Recommendations (721-732)

Appendixes (733-734)

A: Information Gathering: Literature Searches (735-738)

B: Information Gathering: Presentations to the Committee and Outside Meetings (739-756)

C: Methodologic Observations on the Ranch Hand Study (757-763)

D: Committee and Staff Biographies (764-770)

E: Author Index, Chapters 7-11 (771-776)

Glossary (777-783)

Acronyms and Abbreviations (784-789)

Index (790-812)