If you plan to cross the border Sunday morning, the Windsor-Detroit tunnel will be closed for several hours while an emergency response exercise is conducted. Subscribe to CTV News to watch more videos: https://www.youtube.com/ctvnews Connect with CTV News: For live updates and latest headlines visit: http://www.ctvnews.ca/ For breaking news, fast, download the CTV News App: https://www.ctvnews.ca/app Must-watch stories and full programs at http://www.ctvnews.ca/video CTV News on TikTok: https:/