What Confuses Everybody About Secondary Containment

What are the specific requirements for secondary containment of oil containers at SPCC-regulated facilities?

The entire containment system, including the walls and floor, must be capable of containing oil and must be constructed so that any discharge from a primary containment system, such as a tank or pipe, will not escape the containment system before cleanup occurs (40 CFR 112.7(c)).

Exceptions apply to qualified oil-filled operational equipment and flow lines and intra-facility gathering lines at oil production facilities.

Owners and operators of facilities subject to SPCC requirements must provide secondary containment for their bulk storage container installations (except mobile re-fuelers and other non-transportation-related tank trucks) that are capable of holding the contents of the largest single container plus sufficient freeboard to contain precipitation (40 CFR 112.8(c)(2)). What does EPA consider sufficient freeboard?

A 25-year, 24-hour storm event standard is an appropriate standard of sufficient freeboard for most facilities. However, EPA did not promulgate this standard because of the difficulty and expense for some facilities to obtain this storm event data.

Does EPA have an official preference contingency plan or secondary containment for SPCC Planning purposes?

EPA does not believe that a contingency plan is a preferable alternative to secondary containment. EPA’s position is that secondary containment is preferable because it may prevent a discharge that may be harmful. A contingency plan is a plan for action when the discharge has already occurred. However, if secondary containment is not practicable, the owner or operator must provide a contingency plan and take other actions as required.

Must owners or operators of facilities subject to SPCC requirements provide secondary containment, as required by Section 112.8(c)(2), for oil-filled equipment, such as transformers?

Owners or operators must provide secondary containment for all bulk storage container installations, except mobile refuelers and other non-transportation-related tank trucks. Oil-filled electrical equipment is specifically excluded from the definition of “bulk storage container.”

Thus, the secondary containment requirements of 40 CFR 112.8(c)(2) are not applicable to oil filled electrical equipment, such as transformers.

What are the secondary containment requirements for single-compartment and manifolded tanks?

The SPCC requirement for secondary containment requirements relates to the capacity of the largest single compartment or container. Permanently manifolded tanks are tanks that are designed, installed, or operated so that the multiple containers function as a single storage unit. Containers that are permanently manifolded together may count as the “largest single compartment.”