NCG050428_Benchmark Exceedance Tier II Report_20240731

Peterson, Kathryn S
From: Peterson, Kathryn S
Sent: Friday, August 2, 2024 10:34 AM
To: Creaden, Casey
Cc: McCormick, Kelly; Draper, Todd; Mayse, Nate; Hatley, Phillip; Herold, Timothy
Subject: Re: [External] NCG050428 Benchmark Exceedance Tier II Report
Hi Reed,
DEQ has received your notice of benchmark exceedance. Please continue to follow the tier response
procedures listed in General Permit NCG05. Let us know if you need any technical assistance.
Best,
Kathryn Peterson
Assistant Regional Engineer
North Carolina Department of Environmental Quality
Division of Energy, Mineral and Land Resources
Office: [phone]
Mobile: [phone]
Email: [e-mail]
Mooresville Regional Office
610 East Center Avenue, Suite 301
Mooresville, NC 28115
N RTI i r-ARQL�A
d' Department of Erv'yonmental Ou,lity F r
From: Creaden, Casey<[e-mail]>
Sent:Wednesday,July 31, 2024 9:31 AM
To: Peterson, Kathryn S<[e-mail]>
Cc: McCormick, Kelly<[e-mail]>; Draper,Todd <[e-mail]>; Mayse, Nate
<[e-mail]>; Hatley, Phillip<[e-mail]>; Herold,Timothy<[e-mail]>
Subject: [External] NCG050428 Benchmark Exceedance Tier II Report
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Dear DEMLR Regional Office:
The Westlake Royal Building Products—TruExterior Plant 2 located at 175 Circle M Drive in Salisbury, NC has exceeded
the benchmark parameter for TSS at outfall 001 for a second consecutive monitoring period.
TSS for outfall 001 sampled on May 15, 2024, was measured to be 185mg/I compared to the benchmark of
100mg/I
Since this is the facilities second consecutive exceedance for the same parameter at the same outfall, the facility is
required to follow the Tier Two response as documented in Table 4 of Section E-7 of the NCG05 General Permit.
• This emails serves as the notification to the Regional Office within two weeks of becoming aware of the
exceedance date and values.
• The site believes that the current sampling location for outfall 001 is being impacted by upstream pollutants that
are not originating from the site's industrial activities or footprint. Because of this, the facility moved the sample
location for outfall 001 back—25' for the May sample.This allowed the site to sample closer to the nearest point
of discharge before the stormwater leaves the site.The location the site sampled was still past the site's
property line. While moving the sample location helped (outfall 001 in March was measured at 1,500mg/I vs
outfall 001 in May was measured at 185 mg/I (or an 87.67%decrease in pollutant concentration))the location of
the current outfall is not solely representative of the site's stormwater impact. For this reason, the site has
moved the sampling location for outfall 001 back—120' to a defined drainage swale that captures all storm
water runoff coming from the sites finished goods storage yard (please see the document attached in this email
that details the outfall sampling locations, as well as the site's property line and manufacturing footprint).This
sampling location not only captures stormwater runoff from the site's finished product storage, but this
sampling location will still capture potential pollutants coming from truck and vehicle activity entering the plant
(coordinates of the new sampling location are as follows: 35037'46"N : 80031'51"W).The facility believes that
the new outfall location is more representative of the site's industrial activities and footprint and will accurately
represent the potential pollutants generated by the site.This new location should have no upstream offsite
pollutant contamination.
• All findings will be documented in the Stormwater pollution Prevention Plan.
• Since the site triggered the Tier Two response, the site has implemented monthly sampling at outfall 001.The
site collected the first monthly sample at the new outfall 001 location on 7/25/2024. The site will continue to
collect monthly samples until the site has collected three consecutive samples at the outfall below the
established benchmark valve of 100mg/I.
If you have any questions, concerns, or require additional information, please feel free to contact me.
Thanks,
Reed Creaden, CSP I Corporate Environmental
ccreadena-westlake.com I Cell: 601.717.3321
2801 Post Oak, Suite 600 Houston, Texas 77056 1 www.westlake.com
Westlake
91,
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