40 CFR Part 63 Appendix Table 3 to Subpart DDDD of Part 63 | Work Practice Requirements

Table 3 to Subpart DDDD of Part 63—Work Practice Requirements

For the following process units at existing or new affected sources . . .	You must . . .
(1) Dry rotary dryers	Process furnish with a 24-hour block average inlet moisture content of less than or equal to 30 percent (by weight, dry basis); AND operate with a 24-hour block average inlet dryer temperature of less than or equal to 600 °F.
(2) Hardwood veneer dryers	Process less than 30 volume percent softwood species on an annual basis.
(3) Softwood veneer dryers	Minimize fugitive emissions from the dryer doors through (proper maintenance procedures) and the green end of the dryers (through proper balancing of the heated zone exhausts).
(4) Veneer redryers	Process veneer that has been previously dried, such that the 24-hour block average inlet moisture content of the veneer is less than or equal to 25 percent (by weight, dry basis).
(5) Group 1 miscellaneous coating operations	Use non-HAP coatings as defined in § 63.2292.
(6) Process units and control systems undergoing safety-related shutdown on and after August 13, 2021, except as noted in footnote “1” to this table	Follow documented site-specific procedures such as use of automated controls or other measures that you have developed to protect workers and equipment to ensure that the flow of raw materials (such as furnish or resin) and fuel or process heat (as applicable) ceases and that material is removed from the process unit(s) as expeditiously as possible given the system design to reduce air emissions.
(7) Pressurized refiners undergoing startup or shutdown on and after August 13, 2021, except as noted in footnote “1” to this table	Route exhaust gases from the pressurized refiner to its dryer control system no later than 15 minutes after wood is fed to the pressurized refiner during startup. Stop wood flow into the pressurized refiner no more than 15 minutes after wood fiber and exhaust gases from the pressurized refiner stop being routed to the dryer during shutdown.
(8) Direct-fired softwood veneer dryers undergoing startup or shutdown of gas-fired burners on and after August 13, 2021, except as noted in footnote “1” to this table	Cease feeding green veneer into the softwood veneer dryer and minimize the amount of time direct gas-fired softwood veneer dryers are vented to the atmosphere due to the conditions described in § 63.2250(d).
(9) Direct wood-fired PCWP dryers, direct natural gas-fired PCWP dryers, direct-fired lumber kilns, and associated combustion unit bypass stacks on and after July 6, 2029, except as noted in footnote “2” to this table	Conduct an annual tune-up of the combustion unit(s) used to directly fire each PCWP dryer or lumber kiln as specified in §§ 63.2241(d) and 63.2271(c); and continuously monitor an indicator of combustion unit bypass stack usage such as flow damper position or temperature according to § 63.2269(l)
(10) Lumber kilns on and after July 6, 2029, except as noted in footnote “2” to this table	Minimize lumber over-drying to reduce HAP emissions according to § 63.2241(e) by developing and operating according to the O&M plan in § 63.2241(e)(1) and complying with one of the work practice requirements in § 63.2241(e)(3).
(11) Stand-alone digesters on and after July 6, 2029, except as noted in footnote “2” to this table	Use clean steam for injection into digestion process; AND process fiber without addition of HAP-containing or wood pulping chemicals.
(12) Fiber washers on and after July 6, 2029, except as noted in footnote “2” to this table	Process fiber without addition of HAP-containing or wood pulping chemicals.
(13) Log vats on and after July 6, 2029, except as noted in footnote “2” to this table	Meet the work practice requirements specified in § 63.2241(f).
(14) Resinated material handling (RMH) process units on and after July 6, 2029, except as noted in footnote “2” to this table, as applicable	Meet the work practice requirements specified in § 63.2241(g).
¹ New or reconstructed affected sources that commenced construction or reconstruction after September 6, 2019, must comply with this requirement beginning on August 13, 2020, or upon initial startup, whichever is later.
² New or reconstructed affected sources that commenced construction or reconstruction after May 18, 2023, must comply with this requirement beginning on July 6, 2026, or upon initial startup, whichever is later.

[91 FR 41452, July 6, 2026]