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could be used without causing indoor formaldehyde concentrations that result in CEQA <br />cancer risks that substantially exceed 10 per million for occupants with continuous <br />occupancy. <br />Even composite wood products manufactured with CARB certified ultra low emitting <br />formaldehyde (ULEF) resins do not insure that the indoor air will have concentrations of <br />formaldehyde the meet the OEHHA cancer risks that substantially exceed 10 per million. <br />The permissible emission rates for ULEF composite wood products are only 11-15% <br />lower than the CARB Phase 2 emission rates. Only use of composite wood products made <br />with no -added formaldehyde resins (NAF), such as resins made from soy, polyvinyl <br />acetate, or methylene diisocyanate can insure that the OEHHA cancer risk of 10 per <br />million is met. <br />If CARB Phase 2 compliant or ULEF composite wood products are utilized in <br />construction, then the resulting indoor formaldehyde concentrations should be determined <br />in the design phase using the specific amounts of each type of composite wood product, <br />the specific formaldehyde emission rates, and the volume and outdoor air ventilation <br />rates of the indoor spaces, and all feasible mitigation measures employed to reduce this <br />impact (e.g. use less formaldehyde containing composite wood products and/or <br />incorporate mechanical systems capable of higher outdoor air ventilation rates). See the <br />procedure described earlier (i.e. Pre -Construction Building Material/Furnishing <br />Formaldehyde Emissions Assessment) to insure that the materials selected achieve <br />acceptable cancer risks from material off gassing of formaldehyde. <br />Alternatively, and perhaps a simpler approach, is to use only composite wood products <br />(e.g. hardwood plywood, medium density fiberboard, particleboard) for all interior finish <br />systems that are made with CARB approved no -added formaldehyde (NAF) resins. <br />19 of 19 <br />