Worked on the roof top unit at a local Chinese restaurant last month. Notice the safe and easy access from the ladder to the upper level of the roof by way of the acrobatic maneuvering around the electrical service. Not sure what is in that tub, might be old cooking oil but I didn't investigate real close. I had to stand in that water to rewire that unit and replace the capacitor. I charged them a hazardous access fee, a hazardous working environment fee and a bit extra to cover my frustration.