The lead author of a study of dioxin contamination of people who lived near a New Plymouth chemical plant has rejected the latest criticism of the research.
A government study in 2005 measured an unexpectedly high level of dioxin in the blood of a woman who said she moved near the Ivon Watkins-Dow factory at Paritutu in 1978.
Critics suggested her details needed to be checked, but that was not done.
A dioxin campaigner, Andrew Gibbs, says that documents reveal the woman also lived nearby from 1961 to 1963 and that there is now no evidence that people who moved to Paritutu after 1969 were at risk.
But lead investigator Jeff Fowles says other factors point to a later risk of contamination.