# MP Environmental Services, Inc. — Hazardous Materials Safety Interpretation - **operation:** document - **citation:** 25-0045 - **title:** MP Environmental Services, Inc. — Hazardous Materials Safety Interpretation - **source type:** guidance - **agency:** Pipeline and Hazardous Materials Safety Administration - **status:** guidance - **official:** true - **published on:** 2026-03-27 - **effective on:** Not available - **summary:** 25-0045 response to MP Environmental Services, Inc.. - **machine formats:** - **json:** https://regulus.evalyn.ai/document/phmsa-interpretation-25-0045.json - **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-25-0045.md - **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-25-0045 - **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/2026-04/25-0045.pdf **body:** <<>> 1200 New Jersey Avenue, SE Washington, DC 20590 U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration March 27, 2026 Mike Reed MP Environmental Services, Inc. 3400 Manor Street Bakersfield, CA 93308 Reference No. 25-0045 Dear Mr. Reed: This letter is in response to your April 11, 2025 email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to cargo tank certification plates in reserved § 178.340-10. We have paraphrased and answered your questions as follows: Q1. Is it permissible under § 178.340-10 to leave the loading limits section empty or listed as “none” on the cargo tank certification plate? A1. No. Section 178.340-10(b)(1) requires loading limits be listed on the cargo tank certification plate. Determining the loading limits is part of certification required in 178.340-10(b). Q2. Is it permissible under § 178.340-10(b)(1) to provide the loading limit requirements in inches of mercury (inHg) instead of gallons per minute (gpm) or pounds per square inch gauge (psig)? A2. No. The requirements in § 178.340-10(b)(1) specify that the loading limit be expressed in gpm, psig, or both. It is the opinion of this Office that listing the pressure in inches of mercury (Hg) does not meet the intent of § 178.340-10(b)(1). I hope this information is helpful. Please contact us if we can be of further assistance. Sincerely, Alexander Wolcott Acting Chief, Regulatory Review and Reinvention Branch Standards and Rulemaking Division <<>> Jacobson 25-0045 Jones, Jessie Jane (PHMSA) From: INFOCNTR (PHMSA) Sent: Friday, April 11, 2025 12:42 PM To: Dodd, Alice (PHMSA) Cc: Hazmat Interps; Baker, Yul (PHMSA) Subject: FW: Cargo Tank Interpretation Attachments: Arizona inspection 11_26_24-dataQ.pdf; Arizona inspection 11_26_24.pdf; ARIZONA INSPECTION-11.26.24-1.pdf; Arizona Inspection -11-24-24.jpg; 20151107_124601.jpg Hi Alice, Please see the below interpretation request. Let us know if you need anything. Sincerely, Janaye From: Mike Reed Sent: Friday, April 11, 2025 12:02 PM To: INFOCNTR (PHMSA) Subject: Cargo Tank Interpretation You don't often get email from mwreed@mpenviro.com. Learn why this is important 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. Good Morning, I have a request for an interpretation on a cargo tank issue, our driver was given this violation concerning 178.340-10 loading limits. The spec plate on the tank does not have a G.P.M or P.S.I.G markings filled in but does have inches in Mercury box filled in because it is a vacuum loaded tank (picture included). I contacted the manufacturer and spoke to an engineer and he stated they did not have any interpretation or letter from RSPA concerning this issue. I would like to get a ruling on this, since this is a Vacuum loaded tank. I have another Vacuum loaded tank which also has the G.P.M or P.S.I.G with none listed in those areas (picture included) and no HG markings. Is this illegal also? Thank-you for your time. Mike Reed MP Environmental Services, Inc. 3400 Manor Street Bakersfield, CA 93308 Phone 661-393-1088 Cell 661-319-4799 Fax 661-393-0508 1 <<>> DataQs Federal Motor Carrier Safety Administration U.S. Department of Transportation Detailed view of ID# 4901951 Date Entered: 12/04/2024 Report State: AZ Type: Inspection - Incorrect Violation Report Date: 11/26/2024 Report Number: 1034700589 Status: Closed - No Data Correction Made USDOT#: 441566 (SMS) Assigned Agency#: 602-223-2413 Assigned to: AZ DPS Request Summary Requestor Profile Name: MIKE REED Address: 3400 MANOR ST Username: cd004415660000607406 City/State/Zip: BAKERSFIELD, CA 93308 User Role: Validated Motor Carrier Phone: 661-3194799 Company/Agency Name: M P ENVIRONMENTAL SERVICES INC Fax: USDOT#: 441566 (SMS) Email Address: mwreed@mpenviro.com Explanation of Request for Data Review Where did you view the data you want reviewed?: Inspection Report Supporting Document: ARIZONA INSPECTION-11.26.24.pdf Supporting Document: 20161004_072629.jpg Supporting Document: ARIZONA-11.26.24-1.pdf Status: Closed - No Data Correction Made | Federal Violation Code: 178.340(10) Federal Violation Description: SPECIFICATION PLATE Why should the violation be reviewed?: I would like this violation removed, the data plate contains the required information. I have included a copy of the data plate and the title 49 section, if you look at the picture and besides the "loading limits" section, there are three boxes: GPM, PSIG, IN-HG, Since this a vacuum tank and it is loaded by vacuum, the amount is listed as 29 Inches of Mercury, If you look at the " Unloading limits" section and beside it, the Detailed Information from Inspection Record Report State: AZ Reporting Officer ID: 10347 Report Number: 1034700589 City/Location: CHANDLER AZ Date: 11/26/2024 Event County: MARICOPA Event Time: 8:38 AM State: AZ Carrier Information from Inspection Report Carrier Name: MP ENVIRONMENTAL SERVICES INC City: BAKERSFIELD USDOT#: 441566 (SMS) Country: US MC/MX#: State: CA Address (1): 3400 MANOR STREET Zip: 93308 Address (2): Driver Information from Inspection Record Driver Name: JOHN BARWICK <<>> Response List Response Date: 02/05/2025 10:03 AM Status Changed to: Closed - No Data Correction Made Entered By: Chesney Becker Status Prior to Response: Open - In Review Phone: 0-0 Agency Name: AZ DPS Response To: 178.340(10) Supporting Document: NTTC Regs.PDF IN HG. Response Description: Please see the attached regulations that apply. Since this trailer is a MC307/312 tank, per page 243 for loading limits, it has to have an amount in GPM or PSIG - nothing about Response Date: 01/31/2025 07:39 PM Status Changed to: Entered By: MIKE REED Status Prior to Response: Open - In Review Phone: 661-3194799 Agency Name: Validated Motor Carrier Response To: 178.340(10) Response Description: I submitted this almost 2 months ago, Has there been a final determination on this? Documents List Supporting Documents Title Name Document Name Date Uploaded Size Regulations NTTC Regs.PDF 02/05/2025 10:03 AM 3.16 MB Law Enforcement report ARIZONA-11.26.24-1.pdf Original Upload 12/04/2024 10:56 AM 0.90 MB Law Enforcement report ARIZONA INSPECTION-11.26.24.pdf Original Upload 12/04/202410:56 AM 0.95 MB Other evidence to support RDR 20161004_072629.jpg Original Upload 12/04/202410:57 AM 3.51 MB add a response with further details using the buttons above. The more information you provide now, the faster your request can be processed! When the assigned to agency has further questions or requests SYSTEM MESSAGE: You have submitted your request. To help expedite the review process, submit all of the documentation you may have to support your request. You may upload or fax in documentation, or For example, the Safety Measurement System (SMS) Website is updated monthly based on a snapshot of the data. To review crash and inspection records prior to the snapshot, visit the FMCSA Portal. The Pre- any documentation, it will respond above and an email copy will be sent to you. Once the request is closed and a correction is made to the record, you will see it on the next update of the respective system. s://ai.fmcsa.dot.gov/SMS/HelpCenter/Index.aspx#ifaq30897. Employment Screening Program (PSP) report is updated monthly based on the same snapshot used on the SMS Website. For more details about the update schedule, visit the SMS Information Center at http <<>> 11/26/24, 10:12 AM FMCSA - Inspection Platform DRIVER/VEHICLE EXAMINATION REPORT 1550's Arizona Department of Public Safety Inspection Date: 11/26/2024 Report Number: AZ1034700589 Phoenix, AZ 85005 PO Box 18410 Inspection Level: I Start: 08:38 AM MST End: 10:15 AM MST Email/web: returndver@azdps.gov Phone: 602-223-2000 HM Inspection Type: Bulk 400 MANOR STREET 1 P ENVIRONMENTAL SERVICES INC Driver: Barwick, Kelly, John BAKERSFIELD, CA, 93308 License#t D06636224 Location: RIGGS 168 MC/MX#: USDOT#: 441566 State# AZ MilePost: 168 Date of Birth# 04/04/1962 Highway: 1-10 County: MARICOPA State#t: CoDriver: shipper: KINDER MORGAN Fax#: Phone#: 6613931151 License# Bill of Lading: State# Origin: TUCSON, AZ, US Date of Birth# Destination: PHOENIX, AZ, US Cargo: Hazardous Materials VEHICLE IDENTIFICATION Unit Type Make Year State Plate# Equipment ID 2 ST BIEN 1023 MT 3623366 TT PTRB 2023 MT PA28346 VIN GVWR Mileage CVSA# CVSA Issued # OOS Sticker 3297 IXPXDP9X4PD891746 52,000 10BGX5214MFOA272068,000 VIOLATIONS ATTRIBUTABLE TO THE MOTOR CARRIER Vio Code Section Unit Oos Citation # Verify Violations Discovered 172.202A2-HMSPS 172.202 (a)(2) N N aviation, turbine engine 178.340-10-HMP 178.340-10 N HM (Packaging) - MC 306/307/312 certification plate.: SPECIFICATION PLATE MISSING LOADING PSIG AND/OR GAL/MINUTE THE BOXES ARE EMPTY. PICTURE TAKEN 396.5B-L 396.5(b) 2 N U Lubrication - Oil or grease leak: OIL LEAK FROM RIGHT SIDE OF TRAILER SEE PICTURES Hazardous Materials HM Type: Bulk Cargo Tank Specification: 307 Placards Required: Yes HM Class Rep Quantity HM Waste UN/NA# Proper Shipping Name 3 Flammable N N UN1863 HMSP Required? No Fuel, aviation, turbine engine HMSP in Possession of Driver? N/A Special Checks: No Data for Special Checks. otor Carier suited a be prosecute with penalties tip to to as they are applicable to motor carriers and drivers. False certifications of the require e undersigned certifies that all violations noted on this report have been corrected and action has been taken to assure compliance with the Feder Signature Of Repairer X: Facility: Date: Report Prepared By: Tpr Darius Windels. Badge #: Radio#: 10347 KELLY JOHN BARWICK Copy Received By: Page 1 of 2 X- 441566 AZ AZ1034700589 ittps://safespect.fmcsa.dot.gov/#/inspection/confirm 1/2 <<>> § 178.340-10 required in paragraph (b) of this subsection, located on the right side, ments of a different MC Specification, there shall be a metal plate ing the applicable specification is legible at all times the cargo tank is inspection. Details pertaining to the multipurpose configuration shall near the front of each compartment, in a place readily accessible for in complete compliance with such specifications. the plates (or plate assembly) shall be secured in such a manner as to be The mounting of 'paragraph (c) of this section. also be clearly indicated on the manufacturer's certificate required in capable of retaining the plate when subjected to normal operating tion plate shall be used. The plate shall contain at least the informa- conditions. The same marking size and method used on the certifica- requirements of one specification and may be physically altered to (i) If a cargo tank is constructed in accordance with the tion contained below: tered to accommodate a commodity not requiring a specification tank meet another cargo tank specification in this part; or physically al- (tificate required in paragraph (c) of this subsection and the tank mounted such alterations shall be clearly indicated on the manufacturer's cer- EQUIPMENT NECESSARY SPECIFICATION IDENTIFICATION MC multi-purpose plate required in paragraph (b)(2) of this section. Vents Quantity! which does not meet all of the applicable specification requirements, (2) Specification shortages. If a cargo tank is manufactured Fusible Pressure actuated ¡thereby requiring subsequent manufacturing involving the installation Frangible permissible for the original manufacturer to affix the metal certifica- of additional components, parts, appurtenances or accessories, it is Product discharge tion requirements not complied with shall be indicated on the tion plate required in paragraph (b) of this subsection. The specifica- Top Pressure unloading fitting Bottom manufacturer's certificate required in paragraph (c) of this subsection. date such compliance is accomplished shall be stamped on the metal When the cargo tank is finally brought into complete compliance, the Covers certification plate. date and concern (manufacturer or carrier) accomplishing complete The certificate shall indicate the pertinent details, Fill opening Manhole compliance. tank compartment if constructed to a different specification, must (b) Metal certification plate. After July I, 1985, cach cargo tank, or NC shall follow the number required If cargo tank is not so equipped the word "NONE" shall be 'The number required to meet appicable specification If no physical change is required the letters inserted supporting structure. have a metal certification plate attached to its shell or to an integral corrosion, must be located on the left side (on the right side prior to The metal certification plate, not subject 1o the applicable specification requirements and the appropriate multi- (I) Color coding: Those parts which must be changed or added to meet Fach plate shall be permanently affixed by means of brazing, welding, July 1, 1985) near the front in a place readily accessible for inspection. MC 306 RED purpose plate shall be identified using the following colors: marked in characters at least 3/16-inch high by stamping, embossing. soldering, riveting, or other equally suitable means. The plate must be MC 312 YELLOW MC 307 GREEN itself at least the information prescribed in paragraphs (b)(1) and or other means of forming letters into or on the metal of the plate Non Spec. BLUE marking thereon. A combination ASME/DOT certification plate is (b)(2) of this section. The plate may not be painted as to obscure the the appropriate MC Spec. Number Additionally those parts to be changed or added shall be stamped with certificate A certificate signed by a responsible official of the manu- • (C) Manufacturer's authorized. facturer of the cargo tank, or from a competent testing agency, certi- jother specification (or to accommodate a commodity not requiring a (1) If a cargo tank is to be physically altered to meet an- fying that each such cargo tank is designed, constructed and tested in cable specification shall be procured, and such certificate shall be re- accordance and complies with the requirements contained in the appli- ¡fication Identification. Additionally the metal multi-purpose plates specification tank) such combinations shall be indicated beside Speci- employed by him plus one year. In lieu of this certificate, if the motor i rained in the files of the carrier during the time that such cargo tank is required in subparagraph (2) of this paragraph are required quirements of the specification by his own test, he shall similarly carrier himself elects to ascertain that any such tank fulfills the re- Vehicle manufacturer Specification identification ' DOT MC 306; or MC 307; or MC 312 retain the test data. Original test date Date of manufacture Certificate date MC 306 Test pressure Design pressure p.s.1.g § 178.341-1 General requirements. § 178.341 Specification MC 306; cargo tanks. Shell material Head material p.s.1.g. (a) Specification MC 306 cargo tanks must comply with the gencral Weld material specific requirements contained in this section design and construction requirements in §178.340 in addition to the Lining material Maximum product load Nominal tank capacity by compartment (front to rear) Loading limits -. 8.p.m. and/or p.s.i.g. 1bs. US Gal (b) Design pressure. be less than that pressure exerted by the static head of the fully loaded The design pressure of each cargo tank shall not tank in the upright position Unloading limits _ g.p.m. and/or p.s.i.g. § 178.341-2 Thickness of shells, heads, bulkheads and baffles. authorized in $178.340-3 shall be predicated on not exceeding the (a) Material thickness. The minimum thicknesses of tank material ((Al.), Mild Steel (MS): High Strength Low Alloy (HSLA): Austenitic Stainless Steel (SS) The following material designations (or combinations thereot) must be added. Aluminum Alloy example "DOT MC 106-AL. for cargo tanks made of aluminum. A multi-purpose cargo tank For than those indicated in Tables / and Il on page 248. maximum allowable stress level (§178.340-4(a)) but in no case less example would he "Combination MC 306 SS-107 SS " (1) Product density. Il are minimums based on a maximum 7.2 pounds per gallon product The material thicknesses contained in Tabie I and physically altered, metal multi-purpose plates shall be mounted adja- (2) Metal multi-purpose plate. If a cargo tank is to be weight. If the tank is designed to haul products weighing more than 7.2 cent to the metal certification plate readily accessible for inspection. minimum thickness of heads, bulkheads, baffles or shell sheets shall be pounds per gallon, the gallon per inch value used to determine the The mounting of the plates shall be such that only the plate identify- the actual section capacity required in gallons per inch multiplied by 243 <<>> FONG OU LAC. WISTUNSITOS.A MFR'S SERIAL NO. 214М0Д2720 D.O.T. SPEC. DATE MERA ORIG TEST DATE- DESIGN PRESSURE 1 PSg *HEAD MATERIAL MAT EST PRESSUNE 55 PSG Su 200-T. 31A -SS SHELLMATERNL SA30AT: 316 SS WELD MATERINEE MANOLSS LANG LATERLL NOMINAL CAPALU DBYCOMRER I PRONY TO REARE US GALS MAX. PRODUCT LOAD: SUBS. MAX PRODUCTWTS :LES/BALS CLOADNG LIMITS E HONG. CARUNLDADING LIMES CPM! tapu- n" S -2260. <<>> CERTIFICATION PLATE VEHICLE MANUFACTURER_ ACRO I RAILER, CO. MFG. SER. NO.6469 V.I.N. 1A91145c5J1005006 SPECIFICATION IDENTIFICATIONMC-307-312-SS DATE OF MANUFACTURE 9 DATE 1 SERIA ORIGINAL TEST DATE- MODE CERTIFICATION DATE DESIGN PRESSURE 35- VI 18 87 THIS TEST PRESSURE557 ACU PSIG APPL HEAD MATERIAL SA- 40-616 PSIG VEHI SHELL MATERIALSA-240-3161 | 61 TD. LE 4KR. 187 IN. IN E MAN - 8 GA. WELD MATERIAL ER-316L-S1 GRO GRO LINING MATERIALNONE ACI NOMINAL TANK CAPACITY BY COMPARTMENTS (FRONT TO REAR) MAXIMUM PRODUCT LOAD. 020 U.S. GALS. LOADING LIMITS NONE LBS. GPM and/or PSIG UNLOADING LIMITS 35 GPM and/or PSIG O - **truncated:** false - **body characters:** 18033