NCG030433_Tier Response Relief Request to RRO for Copper and Zinc_20221128

Georgoulias, Bethany
From:
Robin Housh <[e-mail]>
Sent:
Monday, November 28, 2022 4:06 PM
To:
Valentine, Thad
Cc:
Georgoulias, Bethany; [e-mail]; Andy Rodak; Madison Paul
Subject:
[External] Request for Relief from Advance Tier Response for Copper and Zinc
Attachments:
2022-11-28 Request for Relief Letter.pdf
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Mr. Valentine,
Please find attached a letter requesting relief from advance tier response for copper and zinc at both Wolfspeed
facilities in Durham County. Justification and supporting documentation is included.
(Hard copy to Mr. Valentine is in USPS mail.)
Please acknowledge receipt of this email.
Sincerely,
__1�41 Robin Housh
Offpd Environmental Manager, EHS
4600 Silicon Drive, Durham, NC 27703
0: [phone] M: [phone]
www.wolfspeed.com
This e-mail message, including any attachments and previous email messages sent with it, contains CONFIDENTIAL and
PROPRIETARY information of Wolfspeed, Inc. or its subsidiaries and may be legally PRIVILEGED. You may not use,
disclose, reproduce or distribute such information without Wolfspeed's authorization. If you have received this message
in error, please notify the sender immediately and permanently delete the original message, its attachments and any
copies thereof.

Wolfspeed.
November 28, 2022
Wolfspeed Inc.
4600 Silicon Drive
Durham, North Carolina, 27703
Mr. Thad Valentine, Environmental Specialist
Division Energy, Mineral, and Land Resources (DEMLR)
NC Department of Environmental Quality
3800 Barrett Drive
Raleigh, NC 27609
RE: NPDES Permits NCG030433 and NCG030541
Request for Relief from Advanced Tier Response for Copper and Zinc
Dear Mr. Valentine:
Wolfspeed, Inc. (formerly Cree, Inc.) operates under General Stormwater Permit NCG030000 for Metal
Fabrication. This General Stormwater Permit was renewed effective 07-01-2021. It was revised to increase
routine sampling from semi-annually to quarterly. It also rescinded Wolfspeed's Letter of Relief from
Advanced Tier Response for Copper and Zinc granted by DEMLR on 09-24-2014. Due to the increased
sampling frequency and the lack of relief from advanced tier response for copper and zinc exceedances,
Wolfspeed now has several stormwater outfalls at both locations requiring Tier III response.
Wolfspeed does not believe the elevated copper and zinc levels originate from the Silicon Drive (DUR) or
Cornwallis Road (RTP) locations based on the following:
• Kymera International (formerly SCM Metal Products, Inc.) is located at 2601 Weck Drive, Research
Triangle Park, NC 27709. The facility smelts copper which could be emiting unregulated concentrations
of copper and zinc to the atmosphere, as reported in their TRI annual report. The copper and zinc may
then be atmospherically deposited to surrounding surface areas such as roofs and parking lots and
"washed" to stormwater outfalls during rain events.
• Copper and zinc compounds are used in wet manufacturing processes at the DUR site. However, the
processes are contained within buildings with no impact to stormwater drains or outfalls.
• Copper and zinc compounds are not used at the RTP site.
• Elevated copper and zinc levels have consistently exceeded the benchmark values in several of the
industrial stormwater discharge outfalls between the two sites. Table 1 and Table 2 (attached) present
the history of copper and zinc exceedances.
• SDO-2, SDO-5, WOLF-1, and WOLF-4 receive the majority of flows from building roofs and paved
surfaces at the respective sites. The copper and zinc values for these outfalls are indicative of
atmospheric deposition.
4600 Silicon Drive
Durham, NC 27703 USA
Main: [phone]

-k-
Wolfspeed.
• Possible mitigation measures are costly and are not guaranteed to reduce the copper and zinc values
below benchmark.
In summary, Wolfspeed does not see a benefit to continue to perform the costly monthly monitoring at both
Wolfspeed facilities beyond the required quarterly occasions or implement costly mitigation measures.
Based on these reasons and the previous Relief from Advanced Tier Response for CopperandZinc granted by
DEMLR, Wolfspeed respectfully requests to resume quarterly sampling stormwater analytical monitoring for
the remainder of our permit terms for the copper and zinc parameters. Wolfspeed will continue to perform
quarterly qualitative monitoring along with the quarterly analytical monitoring for all required parameter,
and Wolfspeed will continue to follow the Tier I — Tier III process should Wolfspeed's sampling results ever
exceed another parameter besides copper and zinc.
Please contact me at 919-407-6103 should you require additional information.
Regards,
Robin L. Housh
Environmental Manager
Wolfspeed, Inc.
Enclosures
• August 4, 2014 Analytical Monitoring Request and Response to August 1, 2014 Meeting Letter
• September 24, 2014 Letter of Relief from Advanced Tier Response for Copper and Zinc
cc: Bethany Geogouhas, NC DEQ DEMLR Central Office
Jim Azarelo, City of Durham Stormwater Inspector
Andy Rodak, TRC Stormwater Consultant
4600 Silicon Drive
Durham, NC 27703 USA
Main: [phone]

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4600 Silicon Drive, Durham, NC 27703 USA
Main: [phone]
August 4, 2014
Attn: Mr. David Parnell
Environmental Senior Specialist
Water Quality, Surface Water Protection Section
North Carolina Department of Environment and Natural Resources
3800 Barrett Drive
Raleigh, NC 277609
RE: NPDES Permits NCG030433 and NCG030541
Analytical Monitoring Request and Response to August 1, 2014 Meeting
Dear Mr. Parnell:
It was a pleasure meeting with you and Bethany Georgoulias to discuss options for Cree's stormwater
monitoring for copper and zinc. This letter is to follow up the verbal request made during our meeting
on Friday, August 1, 2014 at NCDENR offices at 3800 Barrett Drive.
During the meeting Cree presented reasons why the Cree-Durham and Cree-RTP (Research Triangle
Park) facilities, which have both reached Tier Three status under Part II Section B of our NPDES
permits NCG030433 and NCG030541, should return to semi-annual stormwater analytical monitoring
from Tier Two monthly monitoring. Elevated copper and zinc levels, we feel, are not originating from
the Cree-Durham or Cree-RTP facilities based on the following objective evidence:
No copper or zinc compounds are used in Cree's manufacturing processes at either location
which could contribute to these levels;
Cree has performed an extensive review of its buildings and operational areas and no
significant sources of copper or zinc have been identified at either Cree facility that could be
contributing to these levels;
Elevated copper and zinc levels have consistently exceeded the benchmark values in all seven
Cree-Durham industrial stormwater discharge outfalls and all five Cree-RTP industrial
stormwater discharge outfalls, even though several of these outfalls have on -site drainage areas
that contain no buildings, equipment, vehicles, or other possible sources of copper and zinc.
Further, Cree is aware of a copper smelting plant in the vicinity that could be contributing to these
elevated copper and zinc levels. That facility should be taken into consideration by NCDENR as a
potential source of copper and zinc due to atmospheric deposition.

In summary, Cree does not see a benefit to continue to perform the costly monthly monitoring at both
Cree facilities beyond the required four occasions already completed.
Based on these reasons and on the technical discussion held during our meeting on August 1, Cree
formally asks to resume semi-annual stormwater analytical monitoring for the remainder of our permit
terms for the zinc and copper parameters. Cree will continue to perform semi-annual qualitative
monitoring along with the semi-annual analytical monitoring for all required parameters, and Cree will
continue to follow the Tier One -Tier Three process should Cree's sampling results ever exceed another
parameter besides copper and zinc. If NCDENR agrees, and we are able to perform analytical
monitoring of stormwater discharges this next month, we also respectfully request that the next
samples collected be allowed to satisfy our upcoming fall 2014 reporting period.
In addition, during the August 1, 2014 meeting with you Cree asked for a reduction in the number of
outfalls that require analytical monitoring at both the Cree-Durham and Cree-RTP facilities based on
representative outfall status and in a few cases insignificant drainage from certain outfalls.
Cree will plan to submit a separate formal request for this reduction to NCDENR in the near future.
In the interim please advise Cree on our above request to return to semi-annual monitoring
immediately for both Cree-Durham and Cree-RTP facilities.
Please contact me at 919-407-6101 if you need additional information.
Sincerely,
Donna Lazzari
Environmental Manager
Cree, Inc.
Enclosures
cc: Bethany Georgoulias, NCDENR Central Office
Lloyd Smith, Cree, Inc.
Dan O'Connor, PE, URS Stormwater Consultant
Page 2 of 2

NCDENR
North Carolina Department of Environment and Natural Resources
Pat McCrory John E, Skvarla, III
Governor Secretary
September 24, 2014
Ms. Donna Lazzari, Environmental Manager
CREE
4600 Silicon Drive
Durham, North Carolina 27703
Subject. CREE — Silicon Drive
NPDES Permit NCG030433
Relief from Advanced Tier Response
Durham County
Dear Ms. Lazzari:
In response to your discussions with NCDENR Land Quality Section staff, concerning multiple
exceedances of the benchmark values for zinc and copper, Dave Parnell of the Land Quality
Section - Stormwater staff, conducted a compliance evaluation inspection (CEI) on April 8,
2014. The inspection was conducted to determine compliance with the conditions of your
NPDES NCG030433 Stormwater Permit and to discuss any actions that have been or could be
taken to identify and eliminate potential sources of Zinc and Copper related to facility
operations.
Keep in mind that benchmark exceedances are not limit violations or violations of permit
conditions; however, you are obligated to follow the tiered response actions outlined in your
permit. At the time of the inspection, your facility was found to be in compliance with the
tiered response actions and other conditions of the permit, During the inspection, you are
reported to have relayed to Mr. Parnell that you have been unable to determine the source of
the higher levels of the metals, found at the Silicon Drive outfalls. It is notable in this case,
that CREE does not use copper or zinc in the manufacturing processes and the facility has
conducted extensive reviews of your site for external sources of the metals. Your diligence in
attempting to determine and eliminate the zinc source and your continued communication
with Raleigh Regional Office staff is commendable and is documented back to the April 8
compliance evaluation inspection.
Division of Energy, Mineral, and Land Resources
Energy Section • Geological Survey Section • Land Quality Section
1612 Mail Service Center, Raleigh, North Carolina 27699-1612 - 919-707.9200 / FAX: [phone]
512 North Salisbury Street, Raleigh, North Carolina 27604 • Internet: http://portal.ncdenr.org/webAr/
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Based on the aforementioned items, DENR Land Quality Section is granting regulatory relief in
the form of a collapsed Tier 2-'Pier 3 response. Upon receipt of this letter, CREE - Silicon
Drive, may resume the permit specified semi-annual analytical monitoring for the remainder
of the current permit term - which ends October 31, 2017. This decision applies only to the
zinc and copper benchmarks. A benchmark exceedance of any other parameter listed in
your permit will trigger the tiered response actions as described in your permit:
You must notify this office, in writing, within five business days if you become aware of any
significant source of zinc or copper at your facility, that has the potential to be exposed to
stormwater. The relief granted in this letter is contingent upon the current industrial
practices at CREE. If industrial practices change and zinc & copper does become a significant
stormwater exposure risk, then this office reserves the right to withdraw this decision and
reinstate the permit specified tiered response or other actions that may be warranted by the
new set of circumstances.
Retain and append this letter to your Stormwater Pollution Prevention Plan (SPPP) or permit.
Should you have questions or comments regarding the CEI or this letter, please contact Dave
Parnell at [phone] or [e-mail].
Sincerely,
� f
John L. Holley, Jr., PFj, CPESC
Regional Engineer
Rtileigh Regional Office
cc; Stormwater Permitting Program Files
DEMLR Raleigh Regional Office Stormwater Files