What a Closure Plan Covers

A closure plan is the facility’s written procedure for taking a treatment unit out of service in a way that meets California’s Title 22 hazardous waste closure standards. It’s not a remediation plan and it’s not an emergency response plan. It’s a procedural document the facility commits to follow when the unit is permanently decommissioned, when the operation is discontinued, or when the facility moves.

A closure plan typically describes:

• The treatment unit and the waste streams it has handled
• The decontamination procedures for tanks, piping, and containment
• The sampling and analysis steps to demonstrate the unit is clean
• The disposal pathway for residuals, contaminated equipment, and the unit itself
• The final reporting that goes to the CUPA and DTSC

The plan is written to your specific operation. A drum-rinsing unit closes differently from a cyanide-oxidation tank, and the closure plan has to reflect that. Generic, copy-paste closure plans inherited from a prior provider are one of the first things a CUPA inspector flags.

What Goes Into a Closure Cost Estimate

The closure cost estimate is a dollar figure: what it would cost to close your treatment unit under the regulatory method that applies to your facility. Under the PBR and CA tiers, the regulation allows the estimate to reflect costs using the facility’s own staff and equipment, and it may account for salvage value from the sale of wastes, equipment, or other facility assets. The point is to show the regulator that the funds and procedures exist to close the unit properly.

A typical closure cost estimate includes:

For PBR and CA facilities, the regulation allows the estimate to be built using the facility’s own staff and equipment costs, not necessarily third-party contractor rates. The estimate should be updated annually for inflation and for changes in equipment, waste streams, closure scope, or disposal assumptions.

The Annual Update

Closure cost estimates do not sit unchanged for the life of the permit. For facilities operating under Permit by Rule (PBR) and Conditional Authorization (CA), the closure cost estimate is updated every year, with the updated version due to the CUPA by March 1.

The annual update is not a copy-paste exercise. It has to reflect:

• Current labor and disposal rates (using the facility’s own staff and equipment where the regulation permits)
• Changes in waste volume or chemistry at the unit
• Equipment additions, modifications, or replacements since the last update
• Any county-specific cost adjustments (LA County and Santa Clara County, for example, publish updated adjustment letters that the estimate has to incorporate)

When the annual update doesn’t go in, or goes in stale, that’s a documented deficiency the next time the CUPA inspects. We’ve seen single missed updates roll into a multi-item deficiency letter because they cascade into the financial assurance documentation, which has to match the estimate.

Financial Assurance: When the Threshold Triggers It

Once a closure cost estimate crosses a regulatory threshold, your tiered permit also requires financial assurance: documented proof that the dollars to close the unit will actually be available when closure happens.

California recognizes several financial assurance mechanisms. In practice, the most common are:

Which mechanism applies depends on the size of the estimate, the facility’s corporate structure, and what the CUPA will accept. The mechanism has to be documented and on file with the CUPA, and the documented amount has to match the current closure cost estimate. If the estimate goes up at the annual update and the bond or letter of credit doesn’t, the financial assurance is out of compliance even though the closure plan itself looks fine. That mismatch is a deficiency item on its own.

When Closure Becomes Actual Closure

Closure plans and closure cost estimates are paperwork you maintain for years. Actual closure (taking the treatment unit out of service) is a separate project with a separate scope of work. It involves physical decontamination, confirmatory sampling, disposal, and a formal closure certification submitted to the CUPA and DTSC. That work is governed by your closure plan but executed as its own engagement, and it isn’t covered under a standard tiered permitting maintenance contract.

If you’re planning to close a treatment unit because you’re discontinuing the operation, relocating the facility, or selling the property, the closure plan and cost estimate on file are the starting point, not the deliverable. The deliverable is a certified closure. Our hazardous materials facility closure and facility changes guide covers what that engagement looks like in practice.

Closure also frequently overlaps with tank certification. The PE-certified tanks and containment from your tiered permit submittal are decommissioned during closure, and the condition they’re in at the time of closure affects the cost. For more on the tank side of a tiered permit, see tank and containment certification in tiered permitting.

How CDMS Handles Closure Documentation

When a facility brings us in for tiered permitting, the closure plan and cost estimate are built as part of the initial submittal package. They’re informed by the same site walk that produces the tank certification and the contingency plan. When we walk a facility, one of the first things we check is whether the existing closure cost estimate matches the equipment we actually see and the waste streams the operator describes. Mismatches are common, especially at facilities where a prior provider used a generic template instead of writing the plan to the actual unit.

For existing tiered permit holders, we handle the annual closure cost update as a recurring line item. For facilities under our ongoing compliance services, the update is built into the annual cadence so the March 1 deadline doesn’t surprise anyone. For everyone else, we take it as a standalone engagement and turn the package over for the client to file or hand it to us to submit.

Closure cost estimates update on an annual cycle. See keeping your tiered permit current.