On July 6, 2026, the United States Environmental Protection Agency finalized revisions to the Plywood and Composite Wood Products (PCWP) National Emission Standards for Hazardous Air Pollutants (NESHAP) under 40 CFR Part 63, Subpart DDDD. The final rule imposes new hazardous air pollutant (HAP) standards, including production-based, add-on control, operating, work practice, and performance test compliance requirements. Existing affected facilities must comply with the final rule by July 6, 2029.
Who is Affected by the Final Rule?
Affected facilities include PCWP manufacturing facilities that are major sources of HAP emissions or are located at a major HAP source. A PCWP manufacturing facility one that:
- Manufactures plywood and/or composite wood products by bonding wood material (fibers, particles, strands, veneers, etc.) or agricultural fiber, generally with resin under heat and pressure, to form a structural panel or engineered wood product
- Manufactures dry veneer
- Operates a lumber kiln or kilns to dry lumber
Many PCWP manufacturing facilities that were previously exempted will now be regulated by the final rule.
Common PCWP Products Affected by the Final Rule
Plywood and composite wood products include plywood, veneer, particleboard, oriented strandboard (OSB), hardboard, fiberboard, medium density fiberboard (MDF), laminated strand lumber (LSL), laminated veneer lumber (LVL), wood I-joists, kiln-dried lumber, and glue-laminated beams.
Operations Affected by the Final Rule
The final rule applies to a variety of manufacturing operations and activities, including the following:
Material Handling and Preparation
- Onsite storage and preparation of raw materials used for the manufacture of PWCP products, such as resins and adhesive tanks
- Resin and adhesive application and preparation
Wood and Resinated Material Handling (RMH) Processing
- Green end operations
- Stand-alone digesting
- Resinated Material Handling (RMH) process units (including resin tanks, softwood and hardwood plywood presses, engineered wood products presses and curing chambers, blenders, formers, reconstituted wood products board coolers (at existing affected sources), hardboard humidifiers, and wastewater treatment operations). RMH units handle resin or resinated wood material downstream of the point in the PCWP process where resin is applied
- Log vat conditioning
- Fiber washing
Drying
- Refining (including pressurized refiners and atmospheric refiners)
- Drying (including fiberboard mat dryer zones, rotary dryers, hardboard ovens, tube dryers, press predryers, softwood veneer dryer zones, conveyor strand dryer zones, and fiberboard mat drying)
- Direct-fired drying (including direct wood-fired PCWP dryers, direct natural gas-fired PCWP dryers, and direct-fired lumber kilns)
Finishing and Coating
- Lumber kiln drying at PCWP manufacturing facilities or at any other kind of facility
- Finishing operations, such as sanding, sawing, patching, edge sealing, panel trim chipper, and other finishing operations not subject to other HAP standards
Wastewater Treatment
- Coating operations using materials specifically associated with the manufacture of PWCP products
- Onsite wastewater treatment operations associated with the manufacture of PWCP products
Final Rule Requirement Highlights
Compliance with the final rule includes applicable emission limitations, HAP emission calculations inventory development, Operation and Maintenance (O&M) and site-specific planning, work practices, operating restrictions, notifications, recordkeeping, reporting, monitoring, and performance testing. Key new requirements include the following:
Emissions Limitations
- Dryer total HAP emission limitations, including production and reduction-based compliance options (Total HAP includes formaldehyde, methanol, phenol, acetaldehyde, acrolein, propionaldehyde)
- Fiberboard mat dryer and hardboard press pre-dryer individual HAP emission limitations for formaldehyde, and methanol
- Atmospheric refiner individual HAP emission limitations for acetaldehyde, acrolein, formaldehyde, methanol, phenol, and propionaldehyde
- Limitation of methylene diphenyl diisocyanate (MDI) content in resins including emission limitations of MDI from reconstituted wood products presses, tube dryers, and miscellaneous coating operations
- Direct-fired dryer emission limitations for non-mercury HAP metals, mercury (Hg), hydrogen chloride (HCl), and polycyclic aromatic hydrocarbons (PAH)
Work Practices and Operational Requirements
- Biomass direct-fired dryers (i.e., green rotary dryers) dioxin and furan emission limitations
- Work practice and usage monitoring options for RMH process units, coating, and application operations that use materials that contain MDI
- Work practices for log vat conditioning, atmospheric refiners, stand-alone digesters, and fiber washers
- Lumber kiln temperature and moisture monitoring options to limit over-drying, including O&M planning and site-specific planning
- Direct-fired dryer combustion unit annual tune-up, inspection, and maintenance
Monitoring and Compliance
- Direct-fired dryer bypass stack monitoring
- Performance testing and compliance demonstration requirements for all applicable HAP emission limitations
Compliance Timeline
Facilities that were constructed or reconstructed after May 18, 2023, must comply with the new applicable requirements in the final rule by July 6, 2026, with completion of applicable performance testing by January 2, 2027.
Existing facilities have three years to comply and must be in compliance with the final rule by July 6, 2029, although any facility with a lumber kiln that chooses the site-specific planning option will need to prepare and submit the plan within 18 months (by January 6, 2028) and any facility with requirements for “mixed process streams” that elects to comply using control systems has 30 days to submit (by August 6, 2026) a notification of compliance status (NOCS). Mixed process streams are sources with one or more mixed PCWP process streams (comingled emissions from multiple affected sources).
Title V Permitting Implications
Implementation of the final rule will require all affected facilities modify their Title V operating permit, at a minimum, during the renewal cycle. Modification of Title V permits will require incorporation of all new applicable requirements of the final rule.
For support with applicability, compliance, permitting, or to discuss any questions or concerns you may have, please contact Alfredo Arroyo or Katie Milk.
References
USEPA. (2026, July 6). National Emission Standards for Hazardous Air Pollutants: Plywood and Composite Wood Products. 91 Federal Register 41410.
USEPA. (2004, July 30). National Emission Standards for Hazardous Air Pollutants: Plywood and Composite Wood Products. 40 CFR Part 63, Subpart DDDD.
