Pros
Ability for an entry-level person to learn a tremendous amount technically and have exposure to a wide variety of industries and practices. Very challenging work environments posed by outside influences (customers, weather, regulatory agencies) can lead to tremendously close friendships with your coworkers. Opportunity to network in other organizations if you desire.
Cons
Frightening safety vs. profits doublethink. Everyone from the top down will, (sincerely, very often) talk about how safety is priority #1 but will silently encourage squeezing every last drop of blood from the stone. Various parts of management play games to finesse EBITDA figures, leading to junkyard, noncompliant facilities and the financial left hand not knowing what the right is doing. Glengarry Glen Ross sales climate results. The fecal material rolling down hill has no rolling resistance whatsoever in this company, there is a basic failure to lead in middle management, especially. Promotions can be hard to come by and seem arbitrary, compensation and employee development are well behind the curve/industry standard and are low-priority. Example: during the post-Deepwater Horizon period, an event which profited Clean Harbors ~70million dollars per quarter (publicly available estimate, see http://thinkprogress.org/climate/2010/06/18/174703/bp-contractor-army/ )immediately after the disaster, CHES was able to emplace employees numbering in the thousands to help clean up-in months. CHES was still working on reviewing its pay scales after a years-long study/delay.