NC0045993_NOD Response Letter - ATI Specialty Materials Retest 7-28-21_20211028

July 28, 2021

Pace Analytical
9800 Kincey Avenue
Huntersville, NC 28078

To: Matthew Brainard, Project Manager

Dear Mr. Brainard,

This letter is in reference to the Ceriodaphnia dubia chronic pass/fail test that our lab initiated on
May 5, 2021 for ATI Specialty Materials. According to the permit for NC0045993, the testing
requires a 40% test concentration during winter months (November and February) and a 52% test
concentration during summer months (May and August). We inadvertently set the May 2021 test
at 40% instead of the required 52% concentration.

We discovered the error upon notification from Zachary Thomas from the Aquatic Toxicology
Branch of NCDEQ on July 20, 2021. Following this notification, we informed Pace Analytical
and arranged for the test to be repeated on July 28, 2021 at the correct 52% concentration. This
test will be initiated today.

Please let us know if you or the client have any questions.

Thank you,

Brittany Downey
ETT Environmental, Inc.
P.O. Box 16414
Greenville, SC 29606
864-877-6942
[e-mail]