The Environmental Protection Agency (EPA) requires that companies with large fuel and chemical storage tanks perform routine maintenance throughout the tanks' operational lifespan and properly decommission them after a set number of years. These regulations were introduced following multiple incidents involving leaks and explosions.

The rules apply to all tank types, both aboveground and underground. The largest tanks—commonly used for various fuels and petroleum products—pose the greatest maintenance and cleaning challenges. These tanks often feature internal floating roofs and floors that move with the tank’s contents, while the outer shell remains stationary. With diameters ranging from 90 to 200 feet, any spill or incident can lead to significant environmental and safety hazards.

To safely inspect, repair, or decommission these tanks, the following steps are required:

1. Remove all stored product

2. Extract residual sludge and materials

3. Eliminate volatile organic compounds (VOCs) to achieve safe atmospheric conditions (with Lower Explosive Limit (LEL) levels within safe thresholds)

4. Ensure safe entry conditions for personnel and welding operations

While tank owners typically transfer usable product between tanks, residual material—usually 4 to 12 inches of sludge—remains and must be thoroughly cleaned and safely removed. This waste must be treated and disposed of responsibly. The tank atmosphere must then be treated to reduce VOCs and odor, bringing LEL levels to near-zero before any work can begin inside.

PVS TC200 has been developed and field-tested as a strong cleaning and treatment product specifically designed for this application. These formulations effectively remove residual hydrocarbons and sludge, neutralize fuel and chemical contaminants, and produce a treated liquid byproduct safe for discharge to the sanitary system (following aeration and treatment). Treatment times depend on the composition of the waste and job-specific conditions. This process has been successfully applied in tanks containing diesel, gasoline, heating oil, naphtha, petroleum solvents, and other petroleum fractions. It has also been effective in breaking down hydrogen sulfide gas, reducing the need for additional air scrubbing equipment.