Increased CARB Enforcement of Diesel Transport Refrigeration Units (TRUs) Rocks Transporters and Receivers of Refrigerated Shipments in California

Key Takeaways

• CARB is ramping up enforcement of its diesel Transport Refrigeration Unit (TRU) regulations that apply to refrigerated trailers, containers, and trucks, requiring both TRU owners (including those outside California) and large facilities receiving refrigerated shipments to register, report and comply with strict new rules.
• Non-compliance can result in steep penalties—up to $10,000 per day—for both TRU owners and facility operators, with enforcement targeting both in- and out-of-state businesses. The risk extends to any company transporting or receiving refrigerated goods in California.
• Businesses can increase their readiness by verifying that all diesel TRUs are registered and labeled as compliant, and that their facilities a meet quarterly reporting or compliance declaration requirements. Proactive compliance is essential to avoid costly fines and disruptions in refrigerated supply chains.

The California Air Resources Board (CARB) is expected to ramp up enforcement of the amended Airborne Toxic Control Measure for In-Use Diesel-Fueled Transport Refrigeration Units. These rules impose registration, reporting and compliance obligations on both TRU owners and the facilities that receive refrigerated shipments. The requirements of SB 153 are not limited to TRU owners and facility operators in California. SB 153 impacts those based outside California as well as businesses that simply operate facilities in or transport refrigerated shipments into California. All affected parties should take careful note of these requirements.

TRU Owner Registration and Compliance

Under existing California law, all TRU owners, including those based outside California, must register every diesel-powered TRU (i.e., refrigerated trailers, refrigerated intermodal containers) that operate in the state via the Air Resources Board Equipment Registration System (ARBER) system and obtain a CARB Identification Number (IDN). Owners must also affix CARB compliance labels to each registered unit every three years and pay operating fees which CARB uses to support its expanded enforcement activities.

Facility and Consignee Obligations

Current CARB regulations place direct compliance responsibilities on “applicable facilities,” which are defined as refrigerated warehouses or distribution centers of 20,000 square feet or greater, grocery stores of 15,000 square feet or greater, seaport facilities, and intermodal railyards where TRUs operate. These facilities must register with CARB and then satisfy one of two ongoing obligations:

Option 1–Quarterly Reporting: As instituted in April 2024, applicable facilities electing to utilize the Quarterly Reporting option are required to collect all TRU activity occurring within the facility’s fence line or property boundary. These facilities are then required to submit quarterly reports to CARB using CARB’s Applicable Facility Quarterly Reporting Template. Each report must include the CARB IDN (or alternative unique identifier), carrier information and USDOT or CA carrier number for every TRU that has entered the premises during each reporting period. CARB then uses the quarterly reporting to target its enforcement efforts against both in- and out-of-state owners of non-complaint TRUs.

Option 2–Compliance Declaration: Alternatively, under the Compliance Declaration option, an applicable facility may provide a declaration to CARB—under penalty of perjury—that non-compliant TRUs will not be permitted to operate inside the facility. This means the consignee must verify whether each arriving diesel TRU holds a valid CARB compliance label or is listed as compliant in CARB’s ARBER database and refuse to accept shipments carried by unregistered or non-compliant TRUs. For example, an applicable facility must refuse to accept delivery if the TRU owner fails to affix the CARB compliance labels on the TRU. In practice, however, applicable facilities do not favor this option because it must refuse acceptance of perishable goods that could be worth hundreds of thousands of dollars. This makes quarterly reporting the only pragmatic compliance option for the vast majority of affected facilities.

Enforcement and Penalties

CARB has signaled heightened enforcement of these requirements in 2026. Recently, CARB sent invoices via email to current users of ARBER, informing companies of registration fees and that such fees will be utilized to support greater enforcement of TRU regulations.

Should CARB discover non-reported or non-compliant TRUs operating at an applicable facility by using the quarterly reporting or automated roadside monitors, the TRU owner—as well as the owner or operator of the applicable facility—may face penalties under California Health and Safety Code, with escalating penalties for each additional violation. Under state law, CARB has the ability to fine non-compliant parties up to $10,000 per day for infractions.

Recommended Action Items.

We encourage all businesses involved in cold-chain logistics in California that are impacted by SB 153 to confirm that every diesel TRU in their fleet is registered with CARB and displays a current compliance label. And, if a business is operating an applicable facility in California, the business should ensure that it submits the quarterly reporting or the compliance declaration. Benesch will continue to monitor CARB enforcement.