FREDERICTON, New Brunswick (AP) – A federal inquiry into the use of Agent Orange and other toxic herbicides at a New Brunswick military base used by the Maine National Guard has been dealt a serious setback with the sudden resignation of its lead investigator.

Vaughn Blaney announced Tuesday he is stepping down as co-ordinator of the investigation into the effects of herbicide spraying at Canadian Forces Base Gagetown from the 1950s to the 1980s.

Blaney, 67, a former provincial Liberal cabinet minister, was appointed to the inquiry in August but had chaired just two public meetings when his health took a turn for the worse.

“I regret deeply having to take this action now, but I could not in good conscience put my health at risk,” Blaney said in a prepared statement.

“This is very important but stressful work and I didn’t in any way want to put the project in jeopardy by delaying my decision.”

The remaining eight public hearings have been put on hold until Ottawa appoints a new co-ordinator.

Neither Blaney nor anyone close to him would reveal the nature of his illness.

However, it is no secret that the federal investigation into the use of Agent Orange, Agent Purple and a rainbow of other powerful defoliants at the military base is dealing with highly emotional issues.

Hundreds of veterans and civilians who live near the base are claiming their health was harmed by the spray programs.

While the original focus of concern was on U.S. military testing of Agent Orange and other defoliants at Gagetown in 1966 and 1967, it has been broadened to include all herbicide spraying at the base from the mid-1950s until the early 1980s.

Units of the Maine National Guard have been training at the base since 1971. They completed a two-week session there earlier this year and the next planned exercise is in June 2006.

The U.S. military tested Agent Orange, Agent Purple, Agent White and other defoliants at Gagetown in 1966 and 1967 on less than 500 acres of the sprawling base, which occupies much of south-central New Brunswick.

The military also has admitted there were commercial sprays used over a wide area of the base for many years.

Forestry sprays, often loaded with such toxic chemicals as dioxin, were widely used in Canada from the 1950s until the 1980s, when tighter restrictions came into effect.