CARB II is the shorthand for Phase 2 of the California Air Resources Board's Airborne Toxic Control Measure for composite wood products. It sets limits on formaldehyde emissions from hardwood plywood, particleboard, and medium density fiberboard (MDF) used in construction and furniture. Understanding what it covers, why it matters beyond California, and how to verify compliance protects developers from liability and ensures that the buildings they deliver meet increasingly stringent indoor air quality expectations.
CARB II applies to three categories of composite wood products: hardwood plywood, particleboard, and MDF. These materials are used extensively in cabinet construction, in both the box and the door components. The regulation sets emission limits in parts per million based on product type and requires third-party testing and certification by an approved testing body.
Products covered by CARB II must be certified before sale in California, and all products in the supply chain, including finished goods made from covered composite wood products, must use compliant substrates. A cabinet manufactured from CARB II compliant MDF and particleboard meets the standard regardless of where the cabinet is assembled, as long as the substrate suppliers are certified.
In 2016, the Toxic Substances Control Act was amended to require the EPA to adopt regulations for composite wood products that mirror CARB II requirements. Those regulations, known as TSCA Title VI, took full effect in 2018 and apply nationwide. Practically, this means CARB II compliance is not just a California requirement. It is a federal requirement for any composite wood product sold in the US market.
Developers who specify CARB II compliance in their procurement documents are effectively specifying federal compliance, which means the requirement is appropriate for projects in any US state. Manufacturers who cannot provide CARB II documentation are not TSCA Title VI compliant and should not be used for projects anywhere in the US.
The verification process has several layers. The primary documentation is a certificate from an accredited third-party certifier confirming that the composite wood substrate meets CARB II Phase 2 emission standards. CARB maintains a list of approved third-party certifiers whose certificates are acceptable.
For finished goods like cabinets, the manufacturer should be able to provide documentation tracing the composite wood components in their products back to certified substrate suppliers. A manufacturer's statement that their products are CARB II compliant without supporting substrate documentation is insufficient. Cabo Cabinet Group provides full compliance documentation packages including substrate certifications as a standard part of their project delivery process, which is the appropriate practice for any manufacturer serving the US construction market.
Non-compliant composite wood products off-gas formaldehyde at elevated levels, which creates indoor air quality problems that have been linked to respiratory irritation, headaches, and in cases of high sustained exposure, more serious health effects. In residential applications, where occupants spend significant time indoors, the health implications are material.
Beyond the health risk, non-compliance creates legal exposure for developers. Green building certifications like LEED and WELL require low-VOC and CARB-compliant materials. Institutional lenders and affordable housing programs increasingly require compliance documentation. And in the event of indoor air quality complaints, a developer who specified non-compliant materials faces a liability exposure that compliance documentation would have eliminated.
CARB II certification for substrate materials does not expire, but manufacturers are required to maintain ongoing compliance through regular testing and documentation. A certificate issued years ago for a material that has since changed its formulation may not reflect current compliance. When sourcing materials for a current project, confirm that the compliance documentation reflects the current production specification, not a historical one.
No. CARB II applies to composite wood products (hardwood plywood, particleboard, and MDF) but not to solid wood, which does not involve the adhesive resins that generate formaldehyde emissions. Solid wood door frames and drawer boxes are not subject to CARB II, but MDF door cores and particleboard cabinet boxes are.
Request the substrate supplier's third-party CARB II certification certificates, the manufacturer's written statement confirming that the certified substrates are used in the products being supplied, and a statement identifying the third-party certifier whose testing supports the compliance claim. For projects with green building certification requirements, the certifying body may have additional documentation requirements beyond this baseline.
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