Composite wood manufacturers must comply with two different formaldehyde regulations for products sold in the California market. ChemRisk was asked to review how these regulations affected the composite wood industry and to perform indoor air modeling to understand the relationship between the requirements of each rule.

Under the California Safe Drinking Water and Toxic Enforcement Act of 1986 (Proposition 65), all products that contain significant concentrations of chemicals listed on California’s annually published register of chemicals believed to be carcinogenic (including formaldehyde) must be marked with a warning. The safe harbor level represents the theoretical exposure level at which there is no significant increase in risk as adopted by the California Office of Environmental Health Hazard Assessment .

In 2007, a phased regulation known as the Airborne Toxic Control Measure was adopted by the California Air Resources Board (CARB) setting limits on formaldehyde emissions from composite wood products such as hardwood plywood, particleboard, and medium density fiberboard with the first phase initiated beginning in January of 2009.

The hypothetical excess lifetime cancer risk was calculated for each of the Phase I and Phase II CARB standards for hardwood plywood, particleboard and medium density fiberboard using a simplified version of the U.S. Environmental Protection Agency (EPA)/Versar Formaldehyde Exposure Model . Results were compared to Proposition 65’s risk criterion of 1 in 100,000.

Our results suggested that based on expected target operating levels (limits that incorporate a margin such that the products emissions are not likely to exceed the applicable ceiling standard), most hardwood plywood meeting the CARB Phase I standards, as well as all products meeting the CARB Phase II standards, would comply with the Proposition 65 safe harbor level assuming typical conditions.