A safety training exercise left some Waterloo residents wondering what exactly was going on as construction workers were seen rappelling from a crane near Waterloo’s Barrel Yards area on Friday.

The site's foreman says 50 people were involved in today's training, and it’s a standard part of their procedures.

“When all those people are up there with the trainers, people should look up and probably think, 'oh, they’re doing some training or a course, so they know what to do when they have to rescue the crane operator,'” the foreman said.

Crews were back at work by noon following the mid-morning training.