Document 7OKm1LdgNz9Qw5Erd1VRd71ka

MEMORANDUM SUBJECT: CLEAN AIR ACT INSPECTION REPORT USG Interiors LLC, Cloquet, Minnesota FROM: Dakota Prentice, Environmental Engineer AECAB (IL/IN) THRU: Nathan Frank, Section Supervisor AECAB (IL/IN) TO: File BASIC INFORMATION Facility Name: USG Interiors LLC Facility Location: 35 Arch Street, Cloquet, Minnesota Date of Inspection: April 21, 2025 EPA Inspector(s): 1. Dakota Prentice, Environmental Engineer 2. Meaghan Pashen, Environmental Engineer Other Attendees: 1. Nick Axtell, USG Interiors LLC - Environmental Engineer 2. Jenna Leger, USG Interiors LLC - Plant Manager 3. Dan Rahman, USG Interiors LLC - Manager, Reliability & Engineering Contact Email Address: Nick Axtell: naxtell@usg.com; Jenna Leger: jleger@usg.com; and Dan Rahman: drahman@usg.com Purpose of Inspection: to determine compliance with the facility's Part 70 operating permit Facility Type: acoustic ceiling tile manufacturer Facility Name: USG Interiors LLC Facility Location: 35 Arch Street, Cloquet, Minnesota Date of Inspection: April 21, 2025 Regulations Central to Inspection: those requirements of the Air Individual Permit - Part 70 Reissuance (01700006-103) issued by the Minnesota Pollution Control Agency on June 9, 2022 Arrival Time: 1:30 PM Departure Time: 3:20 PM Inspection Type: Unannounced Inspection Announced Inspection OPENING CONFERENCE Presented Credentials Stated authority and purpose of inspection Provided Small Business Resource Information Sheet Small Business Resource Information Sheet not provided. Reason: Not a small business Provided CBI warning to facility Was any information collected during the inspection claimed as CBI? Yes No. The following information was obtained verbally from USG personnel unless otherwise noted. Process Description: The facility produces two main types of acoustic ceiling tile at three main production lines, consisting of two "wet felt" lines and one "constellation" line. Raw materials at wet felt include mineral wool, perlite, starch, and newsprint and at constellation are mineral wool, starch, and latex. At each line, raw materials are added to batch mixers with water to create a slurry. The slurry exiting the mixers feeds continuous production lines where the material thickness is established on a forming line and then moves through a dryer dedicated to each line. The material leaving the oven is cut into 4 foot by 6 foot pieces. These larger pieces then go through finishing steps including grinding, the addition of a surface finish, coating and curing, cutting to final size, and then an additional coating and curing step. Pieces are coated in total enclosures. The finished products are then packaged for shipment. The facility has one additional line, the "laminating" line which is used to produce nonstandard size and color ceiling tiles and has a lower throughput than the three main production lines. Staff Interview: The facility will begin replacing a dryer at a wet felt line in September of 2025. The dryer is being replaced due to its age and associated maintenance and downtime issues. TOUR INFORMATION EPA Toured the Facility: Yes Page 2 of 3 Facility Name: USG Interiors LLC Facility Location: 35 Arch Street, Cloquet, Minnesota Date of Inspection: April 21, 2025 Data Collected and Observations: EPA observed production at a wet felt line and the constellation line. At the constellation line, EPA observed airflow gauges at two coating booths that did not appear to be operating. Photos and/or Videos: were not taken during the inspection. Field Measurements: were not taken during this inspection. CLOSING CONFERENCE Provided U.S. EPA point of contact to the facility Requested documents: The most recent performance test at each emission unit and/or air pollution control equipment; For each total enclosure at the facility: o The results of the M204 test demonstrating initial compliance with total enclosure requirements; and o Any monitoring performed to demonstrate continuous compliance with total enclosure requirements from April 1, 2024 to the present. At the two Constellation spray booths with airflow gauges that did not appear to be working during the inspection: o The date the gauges stopped working; o The date the gauges were repaired; and o Photos, or other documentation, demonstrating the gauges are now working properly. Annual emission reports submitted to MPCA for the years 2019 through 2024; and Annual downtime (hours) at the wet felt line dryer planned for replacement in late 2025 due to maintenance or other unplanned outages for the years 2019 through 2024; and The permit application submitted to MPCA for this dryer replacement project. Concerns: EPA noted concerns about airflow gauges not working at the Constellation spray booths. DIGITAL SIGNATURES DAKOTA Digitally signed by DAKOTA PRENTICE Report Author: ______P_R__E_N__T_I_C_E____13_:3_7:_06_-0_5'_00_' _______ Date: 2025.05.13 Section Supervisor: Frank, Digitally signed by Frank, Nathan _N_a_t_h_a_n_______1_6:_26_:4_8 -_05_'0_0'______________ Date: 2025.05.16 Page 3 of 3