The Waste Management Operators Exam should be an open book exam. Having taken (and passed) the exam when it was open book, I can't imagine trying to recall specific measurements and quantities that can sometimes vary between all the different types of waste facilities covered by the exam. Even today, I need to periodically look up information in the regulations.
The classes, exam prep and exam helped me learn the regulations and more importantly how to look up the information should I need to recall it in the future. The purpose of the exam shouldn't be whether you can memorize all of the details of the regulations, but rather do you understand the fundamentals and know how to look up the specifics.