8/22/25
In the matter of PETITION FOR MODIFICATION
3M Company
3M Corona Plant
I.D. No. 04-00191 Docket No. M-2025-003-M
PROPOSED DECISION AND ORDER
On February 24, 2025, the 3M Company filed a petition seeking modification of the application of 30 Code of Federal Regulations (30 C.F.R.) § 56.13020 at its 3M Corona Plant, Mine I.D. No. 04-00191, in Corona, California. The Petitioner alleges that the alternative method will at all times guarantee no less than the same measure of protection afforded by the standard.
30 Code of Federal Regulations (C.F.R.) § 56.13020 states, in relevant part:
At no time shall compressed air be directed towards a person. When compressed air is used, all necessary precautions shall be taken to protect persons from injury.
The Petitioner’s proposed alternative method consists of implementing a clothes cleaning process that uses regulated compressed air for cleaning miners’ dust-laden clothing. The Petitioner alleges that the alternative method provides a direct reduction of a miner’s exposure to respirable crystalline dust, thus reducing their health risks, while providing no less a degree of safety than that provided by the standard. The proposed alternative method has been jointly developed with and successfully tested by the National Institute for Occupational Safety and Health (NIOSH).
The Mine Safety and Health Administration (MSHA) investigated the merits of the petition and filed a written report of their findings with the Administrator for Mine Safety and Health Enforcement. After a careful review of the entire record, including the petition and MSHA's investigative report, the Administrator for Mine Safety and Health Enforcement issues this Proposed Decision and Order.
FINDINGS OF FACT AND CONCLUSIONS OF LAW
On June 20, 2025, MSHA investigators traveled to the 3M Corona Plant in Corona, California. The purpose of the visit was to discuss the details and merits of the petition under review and to conduct a physical inspection of the subject clothes cleaning booth. During the visit, an overview of the facility’s operations was provided along with an inspection.
The following individuals participated in the investigation at the mine:
1. Phuong Hunter, Environmental Health & Safety (EHS) Manager
2. Loanne Harting, EHS Engineer
The 3M Corona Plant is located in Corona, California. The mine employs a total of 98 employees. The mine works three 8-hour shifts, six days per week.
The miners at the 3M Corona Plant have designated the following representative of miners:
Mr. John McGalliard
18750 Minnesota Road
Corona, CA 92881
jcmcgalliard@mmm.com
A copy of this petition for modification was presented to Mr. McGalliard on February 28, 2025. A copy of the proposed petition for modification has been posted at the mine.
Four miners were interviewed as part of the investigation. No negative comments were provided by any miners during the investigation. Two anonymous comments were provided to MSHA during the Federal Register comment period. Neither of these comments were regarding the technical sufficiency or the safety of the requested modification.
The petitioner states, in relevant part:
This clothes cleaning process uses a regulated compressed air nozzle manifold at less than 30 -pounds per square inch to blow dust from worker’s clothing. This is performed in an enclosed booth, capturing the dust and then delivering it to a stack located outside of the plant. Since the booth is under negative pressure with air moving downward way from the worker’s breathing zone, no dust escapes to contaminate the work environment or other workers. This will provide a direct reduction of a miner’s exposure to crystalline silica dust, thus reducing their health risks while providing no less a degree of safety than that provided by the standard.
The proposed alternative method uses a standalone clothes cleaning system developed under a research effort with the National Institute for Occupational Safety and Health (NIOSH). S.K. Bowling Company participated in the initial clothes cleaning booth (CCB) design and built the prototype. S.K. Bowling has been manufacturing and selling CCBs to mining, mineral milling, and other industrial commodity customers for over a decade.
Studies have shown that when an ore containing quartz or silica-bearing material is milled, work clothing becomes contaminated with respirable dust. Once a worker’s clothing is contaminated, it continuously emits dust, exposing workers, and potentially others with whom they come in close contact, such as family members, to high levels of respirable silica. Dust emission and exposure continues until the worker cleans or changes their clothing.
According to NIOSH, using compressed air inside a properly designed and operated clothes-cleaning booth can quickly, effectively, and safely remove dust from a worker’s clothing without further exposing the worker, co-workers, or the work environment during the cleaning process. This also reduces the risk of cross contamination and exposure to a miner’s family if they were to carry home the dust on their clothing.
NIOSH has determined that a minimum of 2,000 cubic feet per minute (cfm) airflow is necessary to maintain sufficient negative pressure inside a 48-inch by 42-inch booth throughout the entire clothes cleaning cycle. MSHA’s Directorate of Technical Support has advised that airflow through the booth can be measured by using a high-speed anemometer at the exhaust pipe outlet, or by using a pitot tube inserted in or a velometer tapped into a straight section of the discharge pipe downstream of the exhaust from the HEPA filter system. Booth manufacturer S.K. Bowling has advised that negative pressure can also be measured by using a differential pressure gauge. Before a booth is initially placed in operation, the user must measure and record air flow and booth negative pressure as a reference for the future, and to assure that the negative pressure switch is functioning and properly calibrated.
NIOSH has further determined that to ensure worker safety while using the booth, air pressure delivered to the nozzles must be regulated to not exceed 30 pounds ewper square inch (psi). In addition, workers must wear personal protective equipment including a half mask, fit-tested respirator with an N95 filter, or better, hearing protection, and at a minimum, plant-standard eye protection. Additional eye protection, such as safety glasses, is not required for people using a full-face respirator or Powered Air Purifying Respirator (PAPR). When the clothes cleaning booth is built according to specifications, operated under negative pressure, and according to NIOSH’s and the booth manufacturer’s instructions, all dust removed from workers’ clothing is contained and clean, HEPA-filtered air is exhausted. Booth manufacturer S.K. Bowling recommends that selection of a suitable location for the CCB Elite Clothes Cleaning Booth should be done with careful thought.
The alternative method proposed by the petitioner will, at all times, guarantee no less than the same measure of protection afforded to the miner under 30 C.F.R. § 56.13020.
ORDER
Wherefore, pursuant to the authority delegated by the Secretary of Labor to the Administrator for Mine Safety and Health Enforcement and pursuant to Section 101(c) of the Federal Mine Safety and Health Act of 1977, 30 U.S.C. § 811(c), it is ordered that the 3M Company’s Petition for Modification of 30 C.F.R. § 56.13020, consisting of an alternative method of using a stand-alone clothes-cleaning booth at the 3M Corona Plant, is hereby:
GRANTED, conditioned upon compliance with the following requirements.
1. Only miners trained in the operation of the clothes cleaning booth shall be permitted to use the booth to clean their clothes.
2. The Petitioner shall incorporate the NIOSH Clothes Cleaning Process that was published in 2012 and Manufacturer’s Instruction Manual into its MSHA Part 46 Training Plan and train affected miners in the process.
3. Miners entering the booth shall wear eye protection, ear plugs or muffs for hearing protection, and respiratory protection. Respiratory protection means a full-face or half-mask respirator that meets or exceeds the minimum requirements of 30 CFR Parts 56, 57, 60, 70, 71, 72, 75, and 90. As an alternative, the use of a full-face respirator will meet the requirement for eye protection and respiratory protection. A sign shall be conspicuously posted requiring that the above personal protective equipment be used when the booth is entered.
4. Miners entering the booth shall examine valves and nozzles for damage or malfunction and shall close the door fully before opening the valve. Any defects shall be repaired prior to the booth being used.
5. The booth shall be operated under negative pressure. To achieve this, air flow of at least 2,000 cubic feet per minute (cfm) shall be provided and maintained during booth operation and propelled downwards, thereby moving contaminants away from the miner’s breathing zone and into the filter system. Air flow must be verified before putting the booth into operation and on a semi-annual basis thereafter.
6. The airflow measurements shall be recorded and preserved for the active life of the booth, and the records be made available to MSHA upon request. If the flow falls below 2,000 cfm, or negative pressure inside the booth falls below 0.2 psi, the cause shall be promptly determined, and if it can’t be immediately repaired, the booth shall be taken out of service until it can be repaired.
7. Air pressure through the spray manifold shall not exceed 29 psi, or the manufacturer’s recommendation, whichever is lower, for the full 20-second cycle. Two lock boxes, each with a single, plant manager-controlled key, shall be used to prevent tampering with regulators or changing the pressure setpoint.
8. The air spray manifold shall consist of 2-inch square steel tubing with 26 nozzles, capped at the base, and actuated by an electronically controlled ball valve at the top.
9. The upper most spray nozzle shall be located below the booth user’s breathing zone at a height of no more than 56”. A mechanical device that can be manually adjusted shall be used to cover the upper air nozzles as necessary to meet the specific height of the user.
10. Spray nozzles have been recessed into the manifold, which is designed to eliminate the possibility of incidental contact with the air nozzles during the utilization of the clothes cleaning process.
11. The Petitioner shall conduct pre-use, daily, monthly, semi-annual, and annual maintenance checks of the booth in accordance with the recommendations contained in the Manufacturer's Instruction Manual.
12. The air compressor or plant compressed air system supplying the booth’s air receiver shall provide a minimum pressure of 90 psi, to assure the availability of no less than 20 seconds of sufficiently pressurized continuous cleaning airflow.
13. A pressure relief valve designed for the booth’s compressed air receiver shall be installed and maintained in functioning condition.
14. An appropriate hazard warning sign shall be posted on the booth to state, at a minimum, “Respirable Crystalline Dust”.
15. The petitioner shall use a pre-filter and HEPA Filtration System and follow the manufacturer’s recommendations for the maintenance of that filtration system.
a. The Petitioner shall inspect the pre-filter gauge and ensure that it is at an acceptable range between 0 and 2”. If the reading is at or above 2”, then the pleated pre-filters shall be changed. If changing the pre-filters doesn’t reduce the gauge to below 1.25”, the Petitioner shall contact the manufacturer.
b. The petitioner shall inspect the HEPA filter gauge and ensure that it is at an acceptable range between 0 and 1.25”. If the reading is at or above 1.25”, then the HEPA filter cartridge shall be changed. If changing the filter cartridge doesn’t reduce the gauge to below 0.5”, the Petitioner shall contact the manufacturer.
c. Air that has passed though the booth and the pre- and HEPA filter shall be exhausted to the outside through an exhaust stack. The exhaust shall be oriented in a direction that prevents any entrained dust from entering the inlet at the top of the booth.
16. The Petitioner shall maintain a copy of the Manufacturer’s Instruction Manual at the clothes cleaning booth.
Any party to this action desiring a hearing on this matter must file in accordance with 30 C.F.R. § 44.14 within 30 days. The request for hearing must be filed with the Administrator for Mine Safety and Health Enforcement, 200 Constitution Ave NW, Suite 3522, Washington, DC 20210.
If a hearing is requested, the request shall contain a concise summary of position on the issues of fact or law desired to be raised by the party requesting the hearing, including specific objections to the proposed decision. A party other than the Petitioner who has requested a hearing may also comment upon all issues of fact or law presented in the petition and any party to this action requesting a hearing may indicate a desired hearing site.
If no request for a hearing is filed within 30 days after service thereof, the Decision and Order will become final and must be posted by the operator on the bulletin board at the mine.
Timothy R. Watkins
Acting Administrator for
Mine Safety and Health Enforcement
Certificate of Service
I hereby certify that a copy of this proposed decision was served personally or mailed, postage paid, or provided by other electronic means this 22nd day of August, 2025, to:
Phuong Hunter Mr. John McGalliard
EHS Manager – Corona Plant Miner’s Representative
18750 Minnesota Road 18750 Minnesota Road
Corona, CA 92881 Corona, CA 92881
phunter@mmm.com jcmcgalliard@mmm.com
Alexander Bullinger
General Engineer, MSHA Enforcement
cc: Jeffrey Schmidt, Executive Officer, State Mining and Geology Board, California Department of Conservation, 715 P Street, MS 1909, Sacramento, CA
jeffrey.schmidt@conservation.ca.gov