You are subject to this subpart if you own or operate a cellulose products manufacturing operation that is located at a major source of HAP emissions.

(a) Cellulose products manufacturing includes both the Miscellaneous Viscose Processes source category and the Cellulose Ethers Production source category. The Miscellaneous Viscose Processes source category includes all of the operations that use the viscose process. These operations include the cellulose food casing, rayon, cellulosic sponge, and cellophane operations, as defined in §63.5610. The Cellulose Ethers Production source category includes all of the cellulose ether operations, as defined in §63.5610, that use the cellulose ether process.

(b) A major source of HAP is any stationary source or group of stationary sources located within a contiguous area and under common control that emits or has the potential to emit any single HAP at a rate of 9.1 megagrams per year (Mg/yr) (10 tons per year (tpy)) or more or any combination of HAP at a rate of 23 Mg/yr (25 tpy) or more.

(c) The provisions of this subpart do not apply to research and development facilities, as defined in section 112(b)(7) of the Clean Air Act (CAA), regardless of whether the facilities are located at the same plant site as an operation subject to the provisions of this subpart.

(d) For cellulose ether operations, the applicability provisions in paragraph (d)(1) or (2) of this section apply.

(1) The applicability provisions in §§63.100(a) through (f) and 63.160 apply if you are complying with the equipment leak provisions of subpart H of this part.

(2) The applicability provisions in §63.1019 apply if you are complying with the equipment leak provisions in subpart UU of this part.

(e) For cellulose ether operations, the applicability provisions in §§63.100(a) through (f) and 63.110(a), (e) and (h) apply if you are complying with the wastewater provisions in subparts F and G of this part.