Recently, the southeastern United States was slammed by a monster storm—Hurricane Matthew. The destructive hurricane created significant storm surges and caused severe flooding along much of the Atlantic coast. When major flooding occurs, underground storage tank (UST) systems can lift out of the ground, rupture, and release oil or other regulated substances. A single UST release can ruin adjacent private property and rack up huge compliance and enforcement costs.

After severe flooding or a storm like Hurricane Matthew, UST owners and operators must evaluate their tanks before putting them back into operation. These steps are practical measures intended to prevent subsequent accidental releases, ensure safety, and protect public health and the environment, as well as lessen any enforcement penalties.

What to do after a flood

Tank owners should not attempt to access their UST systems until after floodwaters have receded. Local or state officials must also allow reentry into the area before tank owners can begin to assess their tanks for damage. Attempting to access a tank system before the waters have receded or the authorities have granted reentry is extremely dangerous and can be life threatening.

Substantial debris and damage are likely in areas that were inundated with fast-moving water or prolonged standing water. Tank systems can be damaged in a number of ways. For example, tanks can be damaged when:

• Empty or partially full tanks float to the surface;
• Water enters the tank and displaces contents;
• Groundwater forces underground piping to stress and leak;
• Water and floating debris can damage the electrical system;
• Floodwater crests above vent lines and the tank fills with water; or
• Fuel filling caps or vapor recovery caps are loose and water enters the tank.

Because of the variety of possible damages to tank systems, owners and operators should take a close look at every UST system component before restarting or returning to operation.

What to do before restarting a UST

Tank owners may be able to conduct some of the restarting procedures themselves, but many states may require owners to hire a certified tank service provider to conduct the procedures. Before initiating restart procedures, check with your local implementing agency on the requirements of putting systems back into service.

Before a UST system can be returned to service, tank owners and operators must evaluate the following:

• Make sure the power is off to all UST system equipment;
• Determine if the UST released product by inspecting around the tank, secondary containment, sumps, and under-dispenser containment (UDC);
• Determine if the tank has moved by inspecting the tank cover pad for damage;
• Determine if water or debris entered the UST by using a gauging stick and water-finding paste;
• Test fuel in the tank (if ethanol-blended gasoline) if water is found to ensure that the fuel meets specific quality standards; and
• Check the electrical system for damage.

What to do while restarting a UST

If there is no indication that the tank system is leaking or releasing product, it may be returned to service. This is true even if the release detection system is inoperable. However, under such circumstances, tank owners and operators must conduct daily inventory control and reconciliation until the release detection system is repaired.

If the daily inventory control checks show excessive water or loss of product, tank owners must immediately stop using the tank and empty it of product. In addition, UST owners and operators must contact the implementing agency within 24 hours to notify them of a possible spill. Owners can find information on spill reporting through Enviro.BLR.com’s new spill reporting page.

After returning power to the system, tank owners are not finished evaluating their tanks.  Once power is restored, tank owners and operators must assess the following:

• Inspect and determine that all electronic equipment is operating properly;
• Clean and empty spill buckets and containment sumps;
• Perform a tightness test; and
• Test the cathodic protection system.

UST facilities can refer to this checklist for steps to take during tank restart following flood events.

Other actions necessary

Water that is contaminated with any petroleum product or hazardous substance must be disposed of properly. The water should not be discharged or dumped into the street, storm drains, sumps, ditches, or any other area not permitted to receive these liquids. UST tank owners and operators should contact a hazardous waste contractor to properly dispose of contaminated water.

After the tank is up and running again, UST owners and operators must keep and maintain records. Checking the tanks every few hours and keeping a log book can also be helpful if the tank begins to shows signs of lost product.

For additional information on preparing USTs for flood events, owners and operators can refer to this news article on Flooding and Floating USTs, as well as use this checklist to help prepare the UST system.