NC0045993_Correspondence_20240416

April 30, 2024

Mr. Joe Hinkle, EHS Manager
ATI Specialty Materials, LLC
P.O. Box 5030
Monroe, North Carolina 28110

Subject: Draft NPDES Permit
Permit NC0045993
Monroe Facility
Union County
Facility Class I

Dear Mr. Hinkle:

Enclosed with this letter is a copy of the Draft Permit for your facility. Please review the draft very carefully to ensure thorough understanding of the conditions and requirements
it contains.

The Draft Permit contains the following significant changes from your current permit:

The limits for Total Copper were added to the permit based on the results of the Reasonable Potential Analysis.
The quarterly monitoring for Total Cadmium was added to the permit based on the results of the Reasonable Potential Analysis.
The monitoring for Total Lead was increased from Monthly to 2/Month to be consistent with monitoring for other TBEL parameters.
The monitoring for Total Copper was increased from Quarterly to 2/Month due to be implementation of the water quality based Total Copper limit.
The temperature monitoring was added to the permit to determine compliance with 15A NCAC 2B .0200.
The Technology Based Effluent Limits for Total Chromium, Total Fluoride, Total Cyanide, Total Nickel, Total Lead, and Total Zinc have been recalculated based on the latest production
data.
The instream waste concentration was changed from 58% to 51% based on the current flow rate.

Please provide any comments you have regarding the draft permit to this office by June 3, 2024. At this time, the Division is also publishing a notice in the newspapers of general circulation
in Union County, inviting public comment on the draft permit. Following the 30-day comment period, we will review all pertinent comments received and take appropriate action on the
permit modification.

The NPDES Standard Conditions (Parts II, III, and IV) are not included with this draft.  They can be found at the following link if you would like to review them in conjunction with
this draft permit. https://bit.ly/2BZ4xxx

If you have any questions about the NPDES permit process, please contact me at the following e-mail address: [e-mail], or telephone number: 919-707-3606.

Sincerely,

Sergei Chernikov, Ph.D.
Environmental Engineer III
Industrial NPDES Permitting Unit

cc: NPDES Files
Mooresville Regional Office / Surface Water Protection Section (e-copy)
ESS/Aquatic Toxicology Unit (e-copy)
TACU (e-copy)