Canadian authorities have refused to issue a work permit for an American professor who was hired to teach two courses at Carleton University, in Ottawa, allegedly because he was arrested during a labor protest in 1981.

The professor, Thomas F. Juravich, who teaches labor studies at the University of Massachusetts at Amherst, told CBC News that his work permit had been rejected because he was arrested for taking part in a union picket-line protest in the United States.

Canadian officials have refused to comment on the case, but Mr. Juravich said it stemmed from an exchange of information between the U.S. and Canadian governments that could have a chilling effect on lawful protests. He told the CBC that the authorities had asked him for further details and legal documents about the 26-year-old arrest in order to reconsider his application for a work permit.

Mr. Juravich, who is also director of UMass-Amherst’s Labor Relations and Research Center and a contributor to The Chronicle Review, has crossed the Canadian border dozens of times without incident in the past. He was hired by Carleton’s Institute of Political Economy as a visiting professor to lecture on the cultures of Canadian and American labor movements. —Karen Birchard