organic and inorganic chemical storage-tank cleaning services; crude-oil storage-tank cleaning services; refined-hydrocarbon storage-tank cleaning services; railcar cleaning services; heat-exchange services used in the cleaning of organic and inorganic chemical storage tanks and vessels, crude-oil storage tanks, and refined-hydrocarbon storage tanks; nitrogen-generation services used in the cleaning of organic and inorganic chemical storage tanks and vessels, crude-oil storage tanks, and refined-hydrocarbon storage tanks; video-monitoring services used in viewing the inside of organic and inorganic chemical storage tanks and vessels, crude-oil storage tanks, and refined-hydrocarbon storage tanks; hydrocarbon-sludge removal services used in the cleaning of organic chemical storage tanks and vessels, crude-oil storage tanks, and refined-hydrocarbon storage tanks; hydrocarbon-solid removal services used in the cleaning of organic chemical storage tanks and vessels, crude-oil storage tanks, and refined-hydrocarbon storage tanks; analysis services used to estimate the contents of organic and inorganic chemical storage tanks and vessels, crude-oil storage tanks, and refined-hydrocarbon storage tanks; gas-phase monitoring services used to monitor gases inside of organic and inorganic chemical storage tanks and vessels, crude-oil storage tanks, and refined-hydrocarbon storage tanks; cleaning-nozzle installation and mounting services, namely, services for installing and mounting cleaning nozzles on organic and inorganic chemical storage tanks and vessels, crude-oil storage tanks, and refined-hydrocarbon storage tanks