The Alberta government says lead-containing materials were found in an HVAC system of the provincial building in Grande Prairie in September. The public health services operating in the building have been relocated. As Travis McEwan reports, the union representing nurses working there says nurses have exercised their right to refuse unsafe work. »»» Subscribe to CBC News to watch more videos: http://bit.ly/1RreYWS Connect with CBC News Online: For breaking news, video, audio and in-depth