Preparing for the 2026 PCWP NESHAP Amendments

• The rule establishes new emission limits and work practices for previously unregulated hazardous air pollutants and process units
• Facilities may need performance testing, monitoring upgrades, operating plans and control evaluations
• Early planning can reduce capital uncertainty, resource constraints and rushed compliance decisions as July 6, 2029 approaches

On July 6, 2026, the U.S. Environmental Protection Agency finalized amendments to the National Emission Standards for Hazardous Air Pollutants (NESHAP) for the Plywood and Composite Wood Products source category.

The amendments apply to major sources of hazardous air pollutants and address emissions from plywood and composite wood product process units and lumber kilns. The EPA estimates that 219 existing major-source facilities are affected.

The rule adds numerical limits or work practices for pollutants including total hazardous air pollutants, non-mercury metals, mercury, hydrogen chloride, polycyclic aromatic hydrocarbons, dioxins and furans, and methylene diphenyl diisocyanate. It also introduces or expands requirements for performance testing, parameter monitoring, bypass-stack monitoring, recordkeeping and reporting.

The EPA estimates the amendments will reduce hazardous air pollutant emissions by approximately 721 tons per year and volatile organic compound emissions by approximately 8,504 tons per year.

Existing affected sources generally must comply with the new requirements by July 6, 2029. Newer or reconstructed affected sources may already be subject to the requirements.

For many facilities, readiness will require a connected set of technical and operational decisions:

• Confirm which process units, pollutants and standards apply
• Review current control-device and monitoring capabilities
• Identify required test methods and representative operating conditions
• Evaluate sampling locations, operating parameters and data needs
• Determine whether controls, monitors or procedures need modification
• Incorporate new requirements into permits, plans and reporting systems
• Build capital and operating requirements into facility planning

Performance testing establishes more than a point-in-time result. Facilities may also use test conditions to set operating limits that support continuous compliance. An incomplete or poorly sequenced testing plan can therefore affect monitoring, operations and future reporting.

Waiting may compress engineering reviews, procurement, permitting and testing into a narrower window. It may also leave less time to investigate unexpected results or evaluate alternative compliance approaches.

Facilities should begin with a structured applicability and readiness assessment. The objective is to understand what the rule requires, how current systems compare and which gaps could affect operations, capital planning or compliance confidence.

Onterris combines regulatory insight, emissions measurement, environmental analysis, monitoring knowledge and facility-level implementation support. This connected approach helps leaders turn regulatory requirements into a practical plan supported by defensible data.

• Confirm whether the facility is a major hazardous air pollutant source
• Inventory affected process units, lumber kilns and mixed process streams
• Verify construction or reconstruction dates and applicable compliance timing
• Map each source to its emission limits, work practices, testing and monitoring requirements
• Review sampling locations, control devices, monitors, operating records and reporting systems
• Identify permit changes, capital needs and operating-procedure updates
• Build a phased readiness plan that allows time to resolve data or performance gaps