The Ontario Labour Relations Board may decide on Tuesday if three high school strikes including one by Rainbow teachers is illegal. The board began hearing evidence on Thursday and the hearing continues Friday in Toronto. Peel, Durham and Rainbow say the walkout is illegal because the teachers are striking over issues that involve the province and not the boards. The president of the teachers’ union says all the necessary legal steps were followed before the teachers struck on April 27th. The three-week old strike has affected thousands of high school students in Espanola, Manitoulin and Sudbury.