Tank Cleaning

Hydro-cleaning involves pressure-washing and hydro-blast application. Wastewater from these operations creates migratory pathways for contamination to flow on/off-site if containment is not in place or the wastewater flows beyond recapture points. The primary pollutant output of tank cleaning operations is wastewater contaminated with tank residues (e.g., petroleum products, coal, chemicals, compressed gases, fertilizers, pesticides, food products, paints, inks, glues, and soaps) and cleaning solutions.

State and Federal regulations monitor the discharge of pollutants to surface waters or publicly owned treatment works. The wastewater flows covered by the rule include all wash waters that have come into direct contact with the tank or container interior, including pre-rinse, chemical, and final rinse solutions. Additionally, the rule covers wastewater generated from washing vehicle exteriors, equipment, floor washings, and Transportation Equipment Cleaning (TEC) contaminated wastewater at those facilities subject to the TEC guidelines and standards.

Atomized water drift is prevalent in these operations. The spray may drift beyond the cleaned area and contain contaminants such as solvents, toxins, chemicals, and petroleum. Human health impacts include inhaling vapors, neurological damage, and eye and skin contact. Spray drift can also damage soil, groundwater, and natural resources.

Industrial cleaners, solvents, and scalers used for tank cleaning can pose hazards at the jobsite and during storage at the insured’s facility. Cleaners or scale removal chemicals contain one or more acids, such as sulfuric, hydrofluoric, phosphoric, or hydrochloric. Most solvents pose varying toxicity and may contain benzene, petroleum derivatives, perchlorate, tetrachloroethylene, heavy metals, degreasers, and disinfectants. Improper use and mixing of these cleaners could result in a violent reaction, corrosive damage, or release of toxic vapors. Storage container breaches, leaks, and spills caused during transportation to and from jobsites and loading and unloading could contaminate soil and groundwater or run-off into sewer lines or storm drains.

Vacuum trucks used to pump product, sludge, and rinse water out of tanks, or respond to spills and cleanup, may transport wastes off-site for disposal or recycling. Accidents, spills, or leaks during transportation and loading and unloading of any hazardous or contaminated materials could lead to cleanup and third-party liability. Improper disposal of materials collected by the vacuum truck could also result in environmental liability.

Cross-contamination can occur from residual pollutants left on surfaces or spreading contamination to previously unaffected areas, which can be problematic when cleaning tanks load a different and incompatible product. Improper cleaning procedures may also leave an unacceptable residue on cleaners and degreasers.

Improper manifesting of contaminants, including hazardous materials, cleaning fluids, and wastewater, may result in disposal liability. While the generator is responsible for their waste from “cradle to grave,” a contractor may also be liable for improper manifesting and disposal in certain situations. Contractors are also responsible for determining if their spent solvents are subject to the Resource Conservation and Recovery Act (RCRA) hazardous waste regulations. Improper disposal could lead to cleanup and third-party liability, and there may be legal consequences for violating RCRA hazardous waste requirements.