Corruption in the construction industry is endemic regardless of whether it is in government or private industry.  Many, if not all, construction firms just consider it a cost of doing business to pay off inspectors.  I've seen it on road jobs, pipelines, and many other construction jobs I've been on.  Sometimes it's as little as a bottle of whisky to a foreman to sign off on inflated timesheets, or a set of car tires for someone's vehicle.  If it's so prevalent at the lower levels, you can only imagine what is going on at the higher levels.  Based on the experience in Quebec and Montreal, it can be a huge problem.