Kansas Highway Patrol — Hazardous Materials Safety Interpretation

Page 1U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration 1200 New Jersey Avenue, SE Washington, DC 20590 December 19, 2024 Mr. Nicholas Wright Technical Trooper Kansas Highway Patrol 1220 S. Enterprise Olathe, KS 66061 Reference No. 24-0074 Dear Trooper Wright, This letter is in response to your August 26, 2024, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the use of the segregation table for hazardous materials in § 177.848(d). You present a scenario of an organic peroxide with an explosive subsidiary hazard—i.e., “UN3112, Organic peroxide type B, solid, temperature controlled (contains Acetyl cyclohexanesulfonyl peroxide), 5.2, (1)”—and ask whether the hazardous material may be offered for transportation in the same transport vehicle as a Class 3, a Division 6.1 (packing group I with a Class 3 subsidiary (not poisonous by inhalation)), or a Division 6.2 material. Specifically, you ask how to apply the instructions to the segregation table when the § 172.101 hazardous materials table entry for UN3112 does not provide a Division number for the explosive subsidiary hazard. As described in your scenario, a Division 5.2 hazardous material assigned a subsidiary Class 1 that is listed on the organic peroxides table in § 173.225 does not require an approval; additionally, the material is not subject to the explosive approval requirements described in § 173.56 as long as it conforms to all applicable provisions of the table. As such, for the purposes of segregation, it is the opinion of this Office that it is prudent to default to the most restrictive segregation requirements and treat the Class 1 subsidiary as a Division 1.1 material. PHMSA may consider clarifying the instructions in a future rulemaking. I hope this information is helpful. Please contact us if we can be of further assistance. Sincerely, Dirk Der Kinderen Chief, Standards Development Standards and Rulemaking Division#

Page 2Roundtree 24-0074 From: INFOCNTR (PHMSA) To: Dodd, Alice (PHMSA) Cc: Hazmat Interps Subject: FW: Letter of Interpretation request (177.848) Date: Tuesday, August 27, 2024 4:37:31 PM Hello Alice, Please see the below interpretation request. Let us know if you need anything. Sincerely, Janaye From: Nicholas Wright [KHP] <Nicholas.Wright@KS.GOV> Sent: Monday, August 26, 2024 3:03 PM To: INFOCNTR (PHMSA) <INFOCNTR.INFOCNTR@dot.gov> Subject: Letter of Interpretation request (177.848) CAUTION: This email originated from outside of the Department of Transportation (DOT). Do not click on links or open attachments unless you recognize the sender and know the content is safe. Greetings, I am seeking an official interpretation request regarding the segregation table found in 49 CFR §177.848. I located interpretation request #11-0161, in which PHMSA responded to the requestor’s similar question as mine needing additional information to make a determination. I am unable to find a follow-up response from PHMSA on this issue. My question about segregation is specific to an organic peroxide (Division 5.2) with an explosive subsidiary hazard (Class 1). Specifically, the following entry is in question: UN3112, Organic peroxide type B, solid, temperature controlled, 5.2 (1) For the purpose of this issue request, we will hypothesize the technical name for the material is “Acetyl cyclohexanesulfonyl peroxide.” The question for which I am seeking guidance is whether the organic peroxide may be transported in the same transport vehicle as the following hazard classes: Class 3 Division 6.1, PG I, with a Class 3 subsidiary (NOT a material poisonous by inhalation) Division 6.2#

Page 3As the original requestor asked in 2011 in the aforementioned issue request, I am inquiring as to how the Class 1 subsidiary is applied to the segregation table. Since the explosive subsidiary does not have a division, how is the Class 1 used in the table when verifying segregation? The instructions for the segregation table in 177.848(e)(6) direct the user to verify both the primary and subsidiary hazard for materials on the same transport vehicle, but without a division to the Class 1, it seems impossible to apply proper segregation for a material such as UN3112. Thank you in advance for your interpretation and guidance. Technical Trooper Nick Wright, K-100 Kansas Highway Patrol Troop I, Commercial Vehicle Enforcement MCSAP Training & Public Information 1220 S. Enterprise Olathe, KS 66061 Office: (913) 782-8100 Nicholas.Wright@ks.gov#