DERR-2024-012259

Stantec Consulting Services Inc.
2890 East Cottonwood Parkway; Ste 300
Salt Lake City, UT 84121
Tel: [phone]

May 31, 2022

2184 East Pink Coral Circle
Cottonwood Heights, UT 84121

RE: Indoor Air Investigation
Dear
As you are aware, Stantec Consulting Services Inc. (Stantec) was contracted recently by Linde Gas &
Equipment Inc., which was formerly known as Praxair Distribution Inc. (“PDI”), to collect an indoor air
sample for trichloroethylene (TCE) within your basement. In January 2022, you provided written
authorization to Linde for the sampling event that was proposed to you in a December 6, 2021 letter from
Linde’s Mr. Eddie Davis. On behalf of Linde, I am writing to provide you with a summary of the analytical
laboratory test result.

On April 6, 2022, Stantec collected an indoor air sample from your basement using a 6-liter, stainless-steel,
laboratory-certified, SummaTM canister, equipped with a 24-hour flow rate controller provided by the
analytical laboratory, ALS Group USA, Corp. After a sampling timeframe of approximately 24 hours,
Stantec returned to your home to close the canister valve and retrieve the canister for hand-delivery to the
laboratory for analysis of TCE by analytical Method EPA TO-15 utilizing a Single Ion Mode (SIM) analysis
for TCE.

In summary, no TCE was quantified in your air sample at the Laboratory’s Method Detection Limit (MDL)
of 0.27 micrograms per cubic meter (µg/m3) – a laboratory detection limit that is well less than the United
States Environmental Protection Agency’s (US EPA) Residential Indoor Air Vapor Intrusion Screening
Level (VISL) concentration of 0.48 µg/m3. The TCE VISL serves as a Utah Department of Environmental
Quality (UDEQ) Action Level that is used as a benchmark, indicating that supplemental investigation might
be warranted - only if the TCE VISL is actually exceeded.

A copy of the laboratory result report is attached to this letter. If you have questions, please contact me at
[phone].

Respectfully

Stantec Consulting Services Inc.

John G. Russell, III, CPG
Sr. Hydrogeologist, Environmental Risk Manager
Utah Professional Geologist

c. J. Katz/UDEQ
B. Shrestha/E. Davis/Linde
R. Pratt/Stantec