An investigation by the newspaper showed government records of the carcinogenic chemical's use beginning in the 1950s and continuing through the 1970s.
The chemical gained notoriety when U.S. forces began spraying it from aircraft in Vietnam in 1961 to expose enemy positions in dense jungle. Thousands of U.S. soldiers later began showing various illnesses including cancers, liver and skin disorders and impaired immune, endocrine and reproductive functions, the report said.
In Ontario, provincial records show biplanes were used to spray forests as forestry rangers -- including students -- stood on the ground as human markers for the pilots, the Star said.
The provincial Chief Medical Officer of Health was notified of the Star's findings, although tracking down those who worked with the chemical would be difficult because more than 50 years have passed.
Meanwhile, the Canadian government has paid compensation to 3,137 citizens who were exposed to Agent Orange in 1966 and 1967 when the U.S. military used a Canadian military base in Gagetown, New Brunswick, as a testing ground for the chemical.