Constant layoffs. Your team will grow smaller every quarter / year and you'll be expected to pick up the slack over and over again without any change in title or compensation until you quit or become so disillusioned you get fired yourself.
Watch as your SVP or VP hires an old college buddy with zero qualifications to take the job you have been working for years to get.
This company isn't in the business of environmental service, they are in the business of mergers and acquisitions. If your company is being acquired by Clean Harbors... run. They are a cancer that will destroy the heart and soul of any small business in no time. They buy up any decent competition to maintain their stranglehold over their industry.
Their customers hate them but very often have no other options because of their aggressive pursuit of monopoly.
They have the highest turnover in human resources of any company I have ever seen. HR folks come in and very quickly realize what a cancerous cesspool they have arrived at and start looking for a better job.
Eyeing a sales job? Don't do it my friend... and if you do, I tried to warn you.
Looking at an entry level labor job? Prepare to be treated and paid like a prisoner. Good chance you will quit because your manager called you at 2AM on Christmas day and yelled at you for not agreeing to come in to work for the first day off you've had in 50 days.