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Home / News / Newsfeed / Transport Refrigeration Unit Amendments

Transport Refrigeration Unit Amendments

January 27, 2023
image of semi truck with transportation refrigeration unit
For full details on the changes described below, go to: https://ww2.arb.ca.gov/rulemaking/2021/tru2021.

In February 2022, the California Air Resources Board (CARB) adopted amendments to the Transport Refrigeration Unit (TRU) Airborne Toxic Control Measure (ATCM). Owners of TRUs will be required to report their California-operated TRU inventory, label TRU trucks, pay fees, and annually turn over at least 15% of TRU trucks to zero-emission (ZE) TRU trucks (see Table 1 for compliance dates).

Table 1: TRU Compliance Dates

Due Date Percent ZE in Fleet
12/31/2023 15%
12/31/2024 30%
12/31/2025 45%
13/31/2026 60%
12/31/2027 75%
12/31/2028 90%
12/31/2029 100%
Refrigerated warehouses/distribution centers of at least 20,000 square feet, grocery stores of at least 15,000 square feet, seaports, and intermodal railyards with TRU activity must register all TRUs that operate at their facility and pay fees every 3 years.

Beginning December 31, 2022, newly manufactured TRUs must use refrigerant with a global warming potential (GWP) not exceeding 2,200. Beginning in 2023, newly manufactured TRUs must not exceed the particulate matter standard of 0.02 gram per brake horsepower-hour (Tier 4 for 25-50 hp engines). Manufacturers must also provide a comprehensive warranty for ZE TRU trucks.

Trailer TRUs must continue to meet the Ultra-Low Emission TRU (ULETRU) standards every 7 years.

CARB is assessing ZE options for non-truck TRUs and plans to propose a second rulemaking for potential adoption in 2025.



Yorke Engineering specializes in air quality consulting and environmental consulting for stationary and mobile sources, including dispersion modeling, health risk assessments, permitting, emission inventories, air quality compliance systems, etc. Yorke Engineering has assisted over 1,800 customers, including a wide variety of industrial facilities and government organizations throughout California. Learn more about how we can help you here: Air Quality | Yorke Engineering, LLC (yorkeengr.com).

Main Office:

31726 Rancho Viejo Rd. Suite 218
San Juan Capistrano, CA 92675

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