THE VIETNAM ENVIRONMENT

7.1    The use of defoliants, pesticides, herbicides and other chemicals in Vietnam must be viewed in the context of the total operational environment. The use of chemical substances, while aiding prosecution of the war, attracted significant and growing international criticism because of the potential effect on humans. This section provides brief details on the main types of chemicals used in Vietnam.

7.2    Extensive aerial defoliation programmes were undertaken by US aircraft. There is only one recorded case of possible exposure of ANZAC troops to aerially delivered Agent Orange and that is the instance of the Australian C Company 5 RAR on 22 August 1969. It is known that New Zealand troops operated in areas that had been subject to previous defoliation but they were not in those areas at or near the time of defoliation.

7.3    Ground based defoliation programmes were also undertaken to control vegetation around the base area perimeters, weapon pits and on airstrips and landing points. "Local weed killing" around base areas was programmed during the wet seasons.

7.4    From 1962 until June 1971, herbicides were used for defoliation of natural vegetation and to destroy the enemy's in-country food supply. While troops may have been exposed to herbicides, there is only one recorded occasion when on 15 September 1967 troops from V Company, 2 RAR/NZ (ANZAC) might have been in or near an area being sprayed with an unidentified herbicidal type.

7.5    A wide range of insect borne diseases was endemic to Vietnam. They include various forms of malaria, bubonic plague, scrub typhus, dengue and encephalitis. Various measures were employed to combat these diseases, including spraying of insecticides by air and ground based means, trapping and baiting of insect hosts such as rodents, drainage and oiling of mosquito breeding grounds and the adoption of personal protective measures. Insecticides available included malathion, dieldrin, pyrethrins, DDT, diazinon and chlordene. Extensive aerial spraying programmes were undertaken at both Nui Dat and Vung Tau, and ground based spray systems, were used in Nui Dat.

Agent Orange

7.6    In the early years of the Vietnam War, the USA tried several aerial spray trials of herbicide mixtures to evaluate their effectiveness for defoliation and crop destruction. These went under the code names of Agents Purple, Blue, Pink, Green, Orange and White. Some were systemic defoliants, effective against woody and broad leaf plants, while others were non-systemic desiccants used against grasses, bamboo, rice and crops. Typically, they took one - two months to achieve maximum impact

7.7    Agent Orange, a 1:1 mixture of the two chlorophenoxy herbicides 2,4-D and 2,4,5-T eventually became the chemical defoliant most widely used in South Vietnam. Under an aerial spraying programme known as "Ranch Hand" approximately 9% of the total land area was sprayed between 1965 and 1970.

7.8    Debate on the effects of Agent Orange on people involved in the spraying operations began shortly after its introduction in 1965. The primary constituents of the herbicide are known to be of moderate toxicity. However, 2,4,5-T can contain a contaminant dioxin, generally known as TCDD, which is formed as an ineradicable impurity during manufacture and which is known as one of the most toxic man made chemicals. The toxicity varies slightly according to the form of the active ingredient but for 2,4-D in particular a dose of just 6 grams can prove fatal. Toxicity levels are not known precisely, but 2,4-D,the more toxic of the two, is thought to have an acute toxicity estimated at 50-100 mg/kg of body weight. The toxic dose for humans of 2,4,5-T is thought to be about 500mg/kg.

7.9    Both 2,4-D and 2,4,5-T can be absorbed from the gastrointestinal tract after ingestion or by inhalation. Little absorption occurs directly through the skin. Both are readily excreted and do not accumulate in the body.

Vietnam Exposure

7.10    The means by which soldiers might become contaminated with Agent Orange and other defoliants have been examined in many US and Australian reports. The Australian experience closely parallels that of the New Zealanders involved in Vietnam, and for the most part New Zealand soldiers operated with Australian forces (Australia had over ten times the number of soldiers New Zealand had in Vietnam).

7.11    The issue of exposure of Australian troops was fully investigated in several official Australian inquiries in the 1980s. Senate hearings throughout 1982, reported in the publication "Pesticides and the Health of Australian Vietnam Veterans" found no evidence of direct exposure of Australians to Agent Orange or other phenoxy herbicides. They also rejected as "highly improbable " any association of birth defects with exposure to herbicides or insecticides.

7.12    The most comprehensive Australian investigation, the Royal Commission which sat from 1983 to 1985 examined all records of aerial spraying and checked them against the positions of Australian troops on the ground. They concluded that few if any Australians had been exposed to aerial spray, and that "five units of Australians were possibly within half-a-kilometre of spray path on only four days in the seven years of spraying." Detailed investigations of specific claims of direct exposure to Agent Orange could find no supporting evidence.

7.13    It was apparent that New Zealand soldiers who served in Vietnam came into contact with a variety of chemicals and while many were common to every day life, some were peculiar to the Vietnam environment. While evidence suggests that there is no link between Agent Orange and the problems in veterans, it is not known whether there might have been an aggregate effect from the exposure to all chemicals used in the Vietnam environment.

Environmental Protective Measures

7.14    New Zealand Service personnel were not involved in the direct handling of Agent Orange. There were very strict procedures in Vietnam for aerial spraying of Agent Orange from fixed wing aircraft to ensure that, as far as possible, it was not dropped directly onto personnel on the ground.

7.15    Aerial spraying of herbicides and insecticides was also subject to protective measures. Similarly, there were safety precautions within the Australian base areas pertaining to ground spraying of herbicides. Instructions were issued that equipment was to be cleaned; there was to be no smoking while handling or spraying; protective equipment, namely oil resistant gloves, aprons, goggles and masks were to be used; washing or bathing was required on completion of spraying or skin contamination; and utensils were to be sterilised in the event of illness or other medical symptoms. Nevertheless, there were reports of repeated incidents of non-compliance with these protective measures

RADIATION EXPOSURE OPERATION GRAPPLE

8.1    Following the New Zealand Government decision to support the Royal Navy during the Operation Grapple programme of atmospheric testing of British nuclear weapons, two RNZN ships, HMNZS Pukaki and HMNZS Rotoiti, were made available to act as weather ships during the tests in 1957 and 1958. The main task of the frigates was to collect meteorological information essential for the successful and safe conduct of the nuclear tests.

8.2    Operation Grapple consisted of two series of atmospheric tests: three detonations of thermonuclear devices over ocean in the vicinity of Malden Island during May and June 1957; and a further four detonations of thermonuclear devices plus two small nuclear fission ('atomic') devices in the area of Christmas Island (now part of Kiribati) between November 1957 and September 1958. All of the explosions were air bursts conducted at altitudes sufficient to ensure that no part of the fireball touched the surface.

8.3    In the course of the Operation Grapple tests, the New Zealand vessels were stationed at various distances between 20 and 150 nautical miles upwind from ground zero, the point on the ocean surface above which the devices were detonated. These distances were chosen to ensure that the ships crews would be well outside the range of all radiative effects, and to fit with operational requirements for the provision of air/sea rescue if needed, anti-submarine surveillance, thermal flash monitoring, and water sampling. HMNZS Pukaki participated in all nine tests; HMNZS Rotoiti participated in the first four.

Environmental Protective Measures

8.4    While the New Zealand vessels were in the test area, they operated under the safety control of the Royal Navy. By this stage, the British had had a number of years of experience of nuclear testing and comprehensive safety provisions were in place. The RNZN vessels adopted similar safety protocols. Neither HMNZS Pukaki nor HMNZS Rotoiti had primary roles in the test monitoring, and were stationed upwind and well away from areas likely to be contaminated if a surface burst occurred accidentally. The explosions were arranged to take place high in the atmosphere to ensure that there would be no vaporisation or uptake of sea water that might create a contamination hazard or complicate the observations. Gamma rays and other initial radiation from the explosion were well attenuated within a few thousand metres.

8.5    On the ships themselves there were comprehensive safety procedures in place to minimise hazards in case of any unexpected occurrence. The ships could, if necessary, be sealed and they contained wash-down equipment. Radiation detection systems were in place which included both personal film badges, and integrating monitoring instrumentation and ratemeters by which doses at the time were estimated. These recorded no significant radiation. In his report at Appendix Three, Dr Andrew McEwan, Scientific Director, National Radiation Laboratory, noted that analysis conducted by the National Radiological Protection Board in the United Kingdom showed that of 21,358 participants in all British tests, only 1716 had non-zero radiation doses recorded, most of which were insignificant. There is no evidence, nor any suggestion from those responsible for radiological protection, that any RNZN vessel or crew member received any significant exposure to radiation during Operation Grapple.