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CARB Certification for Composite Wood Manufacturers

UL is an approved third-party certifier (TCP) for the California Air Resources Board (CARB) Airborne Toxic Control Measure (ATCM) for composite wood products, helping ensure manufacturers of composite wood products limit the amount of formaldehyde emitted from their products.

Stacked plywood


As an approved third-party certifier (TCP), UL is authorized to conduct inspections and testing to assess composite wood panel manufacturers’ products for compliance to the regulation. The regulation sets formaldehyde emissions limits for hardwood plywood (HWPW), particle board (PB) and medium density fiberboard (MDF).

In the certification process, UL verifies that the manufacturing facility for subject composite wood products are capable of complying with the CARB ATCM emission standards. To receive CARB Certification, manufacturers undergo quarterly inspections and testing, and routine quality control testing at manufacturing locations. Manufacturers that earn certification demonstrate that their panels comply with the emission standards by labeling their panels as CARB Phase 2 compliant.


Products that achieve CARB Certification are verified by a third party to comply with the formaldehyde emissions standards that are required for composite wood products to be sold in California. Finished products containing composite wood products must also contain certified boards if they will be sold in California. This makes certification essential to almost every composite wood panel manufacturer around the world. In addition to opening new markets, manufacturing facilities who earn certification learn to control formaldehyde emissions from their products by establishing on-site quality control testing.

Why UL

UL is a trusted third-party testing and certification company, helping companies navigate the complexities of understanding and meeting emission requirements.

Related standards

  • ASTM E1333 Standard Test Method for Determining Formaldehyde Concentrations in Air and Emission Rates from Wood Products Using a Large Chamber 
  • ASTM D6007 Standard Test Method for Determining Formaldehyde Concentration in Air from Wood Products Using a Small Scale Chamber
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