Dow AgroSciences (NZ) Limited - Issues and Challenges FAQ

Who were Ivon Watkins-Dow (IWD)?
What is 2,4,5-T?
What is Agent Orange?
Did IWD produce Agent Orange in New Zealand?
What are dioxins?
What is 2,3,7,8-TCDD ?
How do dioxin levels in New Zealand compare with the rest of the world?
Didn’t a soil study show that there are elevated dioxin levels in soil close to the plant in New Plymouth?
How did dioxin levels in the blood of local residents compare with community levels in other countries?
Is it true that Dow AgroSciences workers who were around during the 2,4,5-T manufacturing days are likely to have higher blood dioxin levels than local residents?
What health studies have been done involving the company’s workers in New Plymouth?
Some of the local activists have made repeated claims about alleged increases in health effects such as multiple sclerosis and birth defects in the New Plymouth area. Should this be cause for concern?
What about the claims that drums of waste had been illegally buried in the area?
There has been a lot of comment in the news media about past chemical releases at the New Plymouth plant. Is this likely to cause any long term problems?

Who were Ivon Watkins-Dow (IWD)?

Ivon Watkins Limited was established in New Plymouth, New Zealand, in 1944 to supply agricultural products including herbicides and pesticides. The Dow Chemical Company of Midland, Michigan (Dow) purchased a minority shareholding in the company in 1964 at which time it became Ivon Watkins-Dow Limited (IWD). Dow purchased a majority share of the company in 1973 and the remaining shares in 1988. Between 1990 and 1997 the company was known as DowElanco (NZ) Limited when Dow formed a joint venture with Eli Lilly. In January 1998 the company took its present name of Dow AgroSciences (NZ) Limited when Dow acquired Eli Lilly's shareholding.

What is 2,4,5-T?

More correctly known as 2,4,5-Trichlorophenoxyacetic acid, 2,4,5-T is a phenoxy herbicide which was widely used for many years, especially for the control of so-called woody weeds, such as New Zealand Gorse. It was manufactured at New Plymouth from 1962 until late 1987 at which time it was voluntarily phased out in favour of a replacement product.

What is Agent Orange?

Agent Orange was a 50:50 mixture of 2,4,5-T and another phenoxy herbicide, 2,4-D (2,4-Dichlorophenoxyacetic acid) which was manufactured in the United States for use by the American military as a defoliant. The mixture contained varying amounts of the dioxin 2,3,7,8-TCDD as a contaminant, at concentrations as high as approximately 100 parts per million. By contrast the 2,4,5-T manufactured in NZ had a maximum permissible level of 1 part per million, which was reduced in 1972 to one tenth of one part per million. Actual production was consistently well below the maximum permissible level.

Did IWD produce Agent Orange in New Zealand?

No. In 1990 the New Zealand Parliamentary Foreign Affairs and Defence Select Committee examined allegations that Agent Orange had been manufactured in New Zealand and found no evidence to support such claims. As part of this inquiry the company also confirmed that 2,4,5-T manufactured in New Zealand was not sold to the US military.

What are dioxins?

"Dioxins" refer to a group of chemical compounds which share certain similar chemical structures and may share certain biological characteristics. They are an unwanted by-product of combustion, both from natural sources like forest fires and from man-made sources like power plants, incinerators and industrial processes, home-heating and backyard waste burning. In New Zealand the largest single source of dioxins today in the air (39%) is from landfill fires

Dioxins released into the air during combustion can be carried long distances before settling to the ground. As a result, they are found everywhere at low levels. The term "current background" is used to refer to the average levels of dioxins in the environment today.

Dioxins are solids which adhere tightly to soil. They break down in the environment slowly. Because they are so widespread, dioxins exist in every living creature, including humans.

The primary way people are exposed to dioxins is through what we eat, particularly meat, animal fat and dairy products. Our farm animals are exposed to background levels of dioxins mainly though soil they ingest while eating. Through our diet, over time, we store dioxins in the fatty tissues of our own bodies. People can also be exposed to dioxins through airborne emissions but this is a minor source of exposure today.

What is 2,3,7,8-TCDD ?

This is one of the many dioxins. Not all are equally toxic, and some breakdown faster than others. 2,3,7,8 -TCDD is regarded as the most toxic of the dioxins and is also one of the most studied. It can be a contaminant in the production of Trichlorophenol (TCP) which was the key ingredient in the former manufacture of 2,4,5-T.

How do dioxin levels in New Zealand compare with the rest of the world?

The two sources referred to above at the New Zealand Ministry for the Environment website answer this question in detail. In summary, extensive studies of dioxin in blood serum, breast milk, food, marine life and soil all show that dioxin levels in New Zealand are low relative to many other parts of the world, and are generally falling. This is very consistent with other studies in many countries which show that dioxin levels in the environment are declining steadily.

Didn’t a soil study show that there are elevated dioxin levels in soil close to the plant in New Plymouth?

Following a national soil study, a further local study was published in September 2002 which reported on dioxin levels near the New Plymouth plant.

In summary the report concluded that all the residential soil samples showed dioxin below the New Zealand, German and US criteria or guidelines and therefore "not considered a health concern." One soil sample in a public park near the plant was elevated above the USEPA "trigger" guideline for further analysis but below the current NZ criteria. The report concluded any health risk to residents was "negligible".

How did dioxin levels in the blood of local residents compare with community levels in other countries?

The NZ Ministry of Health has commissioned a study into dioxin levels in blood serum of residents who lived near the plant when it was manufacturing 2,4,5-T between 1962 and 1987. An interim report released in September 2004 showed that the small number of individuals tested so far in the suburb of Paritutu had levels ranging from 2 to 33 parts per trillion (ppt) of TCDD and a mean of 10.8 ppt, compared with a NZ background level of 3.5 ppt.

These average levels in the community were greater than the rest of New Zealand but are very consistent with what would be regarded as the normal background in studies in other countries. Dioxin levels in the body tend to increase with age and the most recent analysis published by the US Centres for Disease Control shows that background levels of TCDD for "unexposed" individuals in the United States are 0.3-9.7 ppt for age 15-19, 02-10.9 ppt for age 30-44, 0.3-9.3 ppt for age 45-59 and 0.3-22.6 for age 60 years plus.
(source: Patterson et al., Age specific dioxin TEQ range. Organochlorine Compounds. 2004;66:2878-2883.)

The small sample group so far analysed in the New Plymouth study had an average age of 65.7 years and most had serum dioxin levels which would be considered within the normal background range for their age from this CDC study.

The New Zealand Government itself said "there is no indication of increased disease rates in this population attributable to dioxin" and that "there is no greater risk for people living in that community now than any other part of New Zealand."

For comparison with the maximum level of 33 ppt found in a New Plymouth resident, about 35,000 people at Seveso in Northern Italy who were exposed to dioxin in an industrial accident in 1976 showed serum levels ranging from 2 to 56,000 ppt. Even in the most heavily exposed group in Seveso, with exposure levels far beyond anything found in Paritutu, have shown no overall increase of cancer.

Is it true that Dow AgroSciences workers who were around during the 2,4,5-T manufacturing days are likely to have higher blood dioxin levels than local residents?

That is possible but at this stage we do not know the serum dioxin levels for the site's workers. Overseas studies have shown that occupationally exposed workers do have higher levels but this varies greatly. The largest single plant worker study in the world has monitored about 2200 Dow workers in Midland, Michigan, some of whom developed the disease chloracne, a condition resembling acne which is known to be associated with very high levels of exposure to dioxin. No New Plymouth workers have ever developed chloracne, which suggests local levels of exposure were lower.

It is important to recognize that even among these substantially exposed workers in Midland, there is no evidence beyond chloracne of any increased health impact including cancer, diabetes and heart disease. Furthermore, the incidence of miscarriages, stillbirths, and birth defects among the offspring of male study participants was assessed and found no increase in the risk of these outcomes related to dioxin exposures.

What health studies have been done involving the company’s workers in New Plymouth?

In addition to this IARC study, Dow AgroSciences (NZ) Ltd commissioned a general mortality health study involving everyone who worked on the New Plymouth site at the time. This study was done in association with University of Otago and was completed in April 2008.

The overall conclusion of the research is that, among the workers involved in the study, life expectancy is the same as the rest of the NZ population, deaths from all causes and all cancers is within the normal range expected in NZ, and there is no evidence of increased cancer or other disease related to dioxin exposure.

Some of the local activists have made repeated claims about alleged increases in health effects such as multiple sclerosis and birth defects in the New Plymouth area. Should this be cause for concern?

The Taranaki Medical Officer of Health (Dr Patrick O'Connor) has investigated these and other allegations and has found no evidence to support such claims. His findings have been published in the news media and his reports are available through the Ministry of Health.

What about the claims that drums of waste had been illegally buried in the area?

The Taranaki Regional Council undertook a full detailed study of allegations of illegal agrichemical waste disposal in New Plymouth. The study involved very extensive community consultation as a result of which more than thirty sites were identified for further investigation. The final report was released in August 2001 and concluded that at five sites where disposal was already known to have occurred the clean-up and remediation of these areas was effective. The report also concluded that there was no disposal at the other alleged sites and no evidence of environmental risk at any site or their surroundings. A copy of the report can be obtained from the Taranaki Regional Council.

There has been a lot of comment in the news media about past chemical releases at the New Plymouth plant. Is this likely to cause any long term problems?

There was an explosion in 1972 at a plant producing the herbicide MCPB and a gas release in 1986 at the plant producing TCP, a key ingredient in the manufacture of 2,4,5,-T. Both of these incidents were widely reported at the time and were investigated by independent authorities. In the case of the 1986 incident public hearings were held and a very full public report was published. There is nothing to suggest that either incident caused any long term health or environmental impact and in fact the Ministry of Health interim serum study (September 2004) reported that there is no evidence to determine whether the slightly elevated blood serum levels nearby are the result of regular or single-release emissions.

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