# Stresau Laboratory, Inc — Hazardous Materials Safety Interpretation

**Citation:** 98-0527  
**Type / status:** guidance / guidance  
**Agency:** Pipeline and Hazardous Materials Safety Administration  
**Effective:** Not stated  
**Published:** 1998-02-05

98-0527 response to Stresau Laboratory, Inc concerning 173.127.

## Document text

<<<PAGE 1>>>

=
U.S. Department
of Transportation
Washington, D.C.
400 Seventh Street, S.W.
20590
Research and
Special Programs
Administration
FEB
5 998
Mr. Vince Mendoza
Stresau Laboratory, Inc.
N8265 Medley Road
Spooner, WI 54801-7819
!
Dear Mr. Mendoza:
This is in response to your recent facsimile and to confirm the interpretation we provided you
in our phone conversation last week concerning the classification and testing of fertilizer. As
:
stated, the observation period for the UN Trough Test (Test for determining self-sustaining
exothermic decomposition of fertilizers containing nitrates, Test S.1) is not 20 minutes.
If propagation continues throughout the substance, the fertilizer is considered to meet the
hazard of self-sustaining decomposition. Therefore, in your case where 4-6 hours transpired
before propagation throughout the substance occurred, the product would be considered to
meet the criteria for self-sustaining decomposition.
I hope this information is helpful. If we can be of further assistance, please contact us.
Sincerely,
Director, Office of Hazardous
Materials Standards

<<<PAGE 2>>>

09/30/1997
08:05
9136777065
PAGE 01
STRESAU LABORATORY INC.
Nộ265 Medlay Road, Spooner, WI 54801-7819, Tol. 715-835-2777, FAX 715-635-7979
FAX MESSAGE
$53
Stresau Lab - Dunn Lake
HazMat Test Dept.
Ext. 166
Fax Number: 704000= 4979
(913) 677-7065
verification: 725763524297
(913) 677-3060
•FAX TO:
MR: BOB RICNARDS
COMPANY :
DOT
FAX NUMBER: 202-366-5713
FOLLOW UP NUMBER: -
202-366-0656
FROM: Vince Mendoza
DATE:
•30
55PT 97
# of pages
. + cOVeI sheet = _ /
pages
HELLO MR: RICHAROS: FoLLowup Tö our CALL THI5 MoRNIng:
I An. Sseking VEnIficopioN As to DOT's IntErprstAtIoN of
THE CRITERA OF SELE SUSTAMAg DESOMpOSITiIN Pf A
FERTILIZER N THS TRongh TEST, UN ToST S.1.
PICASE Fax your DapArTManTS cOmmoNTS, TOnE AT
THE ABOVE fAX NuMBEr.
I An oN TRAvEL So THo NunBoR
rs noT.
my office.
Thank you fur your Altontion
•
5143
q9l

## Provenance

- Official: Yes
- Source: <https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/1998/980527.pdf>
- Source ID: `phmsa`
- SHA-256: `d2212ca676dec804b66b32e9e01fb2c3d58186c5cbd23009bf135dfa2e43bcc3`
- Retrieved: 2026-08-20T00:59:31.977Z
- Exported: 2026-08-23T16:36:20.142Z
- Document slug: `phmsa-interpretation-98-0527`

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