# Diablo Canyon Power Plant — Hazardous Materials Safety Interpretation **Citation:** 26-0041 **Type / status:** guidance / guidance **Agency:** Pipeline and Hazardous Materials Safety Administration **Effective:** Not stated **Published:** 2026-08-19 26-0041 response to Diablo Canyon Power Plant concerning 171.8, 172.704. ## Document text <<>> 3/31/26, 10:56 AM USDOT Mail - Fwd: 172.704 Interpretation Request Larson, R. 26-0041 Fwd: 172.704 Interpretation Request 1 message INFOCNTR (PHMSA) To: "Baker, Yul (PHMSA)" Cc: Hazmat Interps Good afternoon, Please see the following request for a letter of interpretation. Let us know if you need anything else. Best, Aminah ---------- Forwarded message --------- From: Hewitt, Tim (he/him/his) Date: Mon, Mar 30, 2026 at 11:53 AM Subject: 172.704 Interpretation Request To: infocntr@dot.gov Mon, Mar 30, 2026 at 3:18 PM Classification: Internal Pipeline and Hazardous Materials Safety Administration U.S. Department of Transportation Office of Hazardous Materials Standards 1200 New Jersey Avenue, SE Washington, DC 20590 Subject: Request for Clarification Regarding Software‑Specific Training Requirements Under 49 CFR 172.704 To Whom It May Concern, Diablo Canyon Power Plant (DCPP), operated by Pacific Gas and Electric Company, is requesting clarification regarding the applicability and scope of software‑specific training requirements under 49 CFR 172.704, as referenced in PHMSA correspondence No. 23‑0057 dated September 28, 2023. This request is being made to ensure continued compliance with the Hazardous Materials Regulations (HMR) and to establish clear boundaries for training expectations related to software used in hazardous materials shipping activities. PHMSA’s interpretation in No. 23‑0057 states that hazmat employees must be trained on any software used to perform functions subject to the HMR. While DCPP maintains a robust, procedure‑driven shipping program with documented qualification, oversight, and verification, we seek clarification on how PHMSA intends this interpretation to apply to software used primarily for data entry within a controlled procedural framework. Context of Software Use at DCPP DCPP utilizes two primary categories of software in support of HMR‑related activities: 1. Validated Excel‑based calculation tools These spreadsheets contain embedded formulas that perform HMR‑related calculations for simplistic items. End users do not modify formulas or logic; they only enter data into designated fields. This level of interaction is comparable to using a calculator or other general‑purpose office software. 2. Vendor Software The vendor software is used to classify material and generate shipping documentation for more complicated or higher activity items. https://mail.google.com/mail/u/0/?ik=76db1044b4&view=pt&search=all&permthid=thread-f:1861115813067084035&simpl=msg-f:1861115813067084035 1/2 <<>> 3/31/26, 10:56 AM USDOT Mail - Fwd: 172.704 Interpretation Request User interaction is limited to following detailed, step‑by‑step procedures (e.g., enter value X, select option Y , verify box Z is checked). The process is fully governed by approved procedures, and personnel qualification includes demonstration of proficiency. Personnel receive procedure use and adherence training embedded in many aspects of their reoccurring training. When the software is updated, it is verified and validated prior to implementation, and procedures are updated to reflect any changes. Procedure changes are communicated to affected plant personnel. In both cases, the software functions as a data‑entry interface, with the regulated decision‑making and compliance determinations controlled by procedures, not by user discretion. DCPP may also use web browser software to review the HMR to aid with proper decision making and calculator software to perform mathematical HMR functions. Request for Clarification To ensure consistent application of PHMSA’s expectations, DCPP respectfully requests clarification on the following points: 1. Does PHMSA consider data entry only use of software, where the employee follows detailed procedures and does not modify formulas, logic, or regulatory determinations, to require recurring software specific training under 49 CFR 172.704? 2. If procedures govern the steps performed in the software, does PHMSA consider procedure‑use training to satisfy the intent of “training on the software”? 3. If recurring software specific training is required even when procedures control the process, what criteria should be used to determine the threshold of software that no longer requires training? Many software platforms used during HMR related tasks, such as Microsoft Office applications, calculators, web browsers, and specialized vendor software, are capable of performing regulated functions depending on configuration and use. DCPP seeks clarification on how to determine which software platforms PHMSA considers to require specific training and which are considered incidental tools that do not require recurring training. DCPP is committed to maintaining full compliance with DOT regulations and ensuring that personnel performing HMR related functions are properly trained and qualified. We believe that clear guidance on the boundaries of software‑specific training requirements will help ensure consistent implementation across the industry and avoid unnecessary or unintended training burdens. We respectfully request a written response to this inquiry. PHMSA’s interpretations are an essential resource for regulated entities, and we appreciate your continued support in helping facilities apply the HMR correctly and consistently. If additional information is needed, please contact me at (805) 556-5034 or timothy.hewitt@pge.com. Thank you for your time and consideration. Regards, Timothy Hewitt Senior Advising Radiation Protection Engineer Diablo Canyon Power Plant 9 Miles NW Avila Beach Avila Beach, CA 93424 You can read about PG&E’s data privacy practices at PGE.com/privacy. https://mail.google.com/mail/u/0/?ik=76db1044b4&view=pt&search=all&permthid=thread-f:1861115813067084035&simpl=msg-f:1861115813067084035 2/2 <<>> 1200 New Jersey Avenue, SE Washington, DC 20590 U.S. Department of Transportation Pipeline and Hazardous Materials Safety Administration August 19, 2026 Timothy Hewitt Senior Advising Radiation Protection Engineer Diablo Canyon Power Plant 9 Miles NW Avila Beach Avila Beach, CA 93424 Reference No. 26-0041 Dear Mr. Hewitt: This letter is in response to your March 30, 2026 email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to hazmat employee training. Specifically, you seek clarification on the applicability and scope of software‑specific training requirements under § 172.704, as referenced in a previous Pipeline and Hazardous Materials Safety Administration (PHMSA) letter of interpretation (LOI) (Ref. No. 23‑0057).1 You state that it is your understanding that LOI 23-0057 dictates that hazmat employees must be trained on any software used to perform functions subject to the HMR. You describe two categories of software used at your company: validated Excel-based calculation tools and vendor software used for hazard classification and shipping paper generation. You note that in both cases, user interaction is limited to data entry governed by detailed step-by-step procedures, where compliance determinations are controlled by those procedures rather than user discretion. You ask a series of questions regarding the § 172.704 training requirements. We have paraphrased and answered your questions as follows: Q1. Does data entry only use of software—where an employee follows detailed procedures and does not modify formulas, logic, or regulatory determinations—require recurring software-specific training under § 172.704? A1. The answer depends on whether the individual meets the definition of a “hazmat employee” in § 171.8. As clarified in a previous LOI (Ref. No. 16-0136), an individual whose role is strictly limited to transcribing or inputting data—without exercising any discretion or making regulatory determinations—is generally not considered a hazmat 1 WMG Inc., Letter of Interpretation Reference Number 23-0057, available at: https://www.phmsa.dot.gov/regulations/title49/interp/23-0057. <<>> employee and is not subject to HMR training requirements.2 However, if an employee uses software to perform a regulated function (e.g., classifying hazardous material or generating a shipping paper) and is responsible for the accuracy of that information, they are considered a hazmat employee. In accordance with § 172.704(a)(2), function-specific training is required for the tasks an employee performs. Lastly, as stated in LOI 23-0057, if a hazmat employee uses specific software to meet HMR requirements, they must be trained in how to use that software correctly to ensure the resulting output is compliant. Q2. If procedures govern the steps performed in the software, does procedure-use training satisfy the intent of “training on the software” mentioned in LOI 23-0057? A2. Yes. For those determined to be hazmat employees, function-specific training required by § 172.704(a)(2) must be tailored to the actual tasks performed by the employee. If the software use consists entirely of following a specific, approved procedure that dictates every input and verification step, then documented training on those procedures satisfy the function-specific training requirement for that task. Q3. If recurring software-specific training is required even when procedures control the process, what criteria determine the threshold for software that no longer requires training? A3. Training is required for any tool that is integral to a hazmat employee's performance of a regulated function. General-purpose tools like calculators or web browsers used for reference generally do not require specific training under § 172.704, provided the employee is already proficient in their basic operation. When a specialized tool (like your Excel-based calculation tools or vendor shipping software) is used to automate HMR compliance, the training must be sufficient to ensure the user understands how to input data correctly and recognize if the software is producing an error or an illogical result. 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 2 DuPont Corporation Center for Safety, Health, and Environment (SHE), Letter of Interpretation Reference Number 16-0136, available at: https://www.phmsa.dot.gov/regulations/title49/interp/16-0136. ## Provenance - Official: Yes - Source: - Source ID: `phmsa` - SHA-256: `53fceb808818486e3549991886f0de039713476f5a8dc90826187117d19fdb39` - Retrieved: 2026-08-20T00:59:31.977Z - Exported: 2026-08-23T00:01:56.499Z - Document slug: `phmsa-interpretation-26-0041` ### Source metadata ```json { "materialSubtype": "interpretation", "interpretationArea": "hazardous_materials", "representation": "full_text_from_official_pdf", "companies": [ "Diablo Canyon Power Plant" ], "individuals": [ "Timothy Hewitt" ], "refIds": [ "26-0041" ], "catalogDates": [ "2026-08-19" ], "catalogParts": [ 171, 172 ], "catalogRowCount": 2, "sourceRecordUrls": [ "https://www.phmsa.dot.gov/node/84561" ], "linkedAttachmentUrls": [], "unavailableResponseUrls": [], "duplicateRepresentationUrls": [], "citedSections": [ "171.8", "172.704" ], "catalogPageUrls": [ "https://www.phmsa.dot.gov/regulations/title49/section/1718", "https://www.phmsa.dot.gov/regulations/title49/section/172704" ], "pdfUrls": [ "https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/2026-08/260041.pdf" ], "representations": [ { "viewUrl": "https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/2026-08/260041.pdf", "detailUrl": null, "detailHtmlPath": null, "pdfUrl": "https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/2026-08/260041.pdf", "pdfArtifactPath": "data/sources/phmsa-interpretations/26-0041-11cb8c1148.pdf", "pdfArtifactSha256": "c495fd530f36ca11dedf24a489fe0f6148d2dcdaebecb1d6894ba63ddd418dee", "extractedTextPath": "data/sources/phmsa-interpretations/26-0041-11cb8c1148.v2.txt", "extractedTextSha256": "3d2b97d727d22410ada30a5e1e7fcd97987f90fc70578f4254747163fb445ad2", "pageCount": 4, "extractionVersion": 2 } ], "caveat": "Interpretations apply regulations to the facts presented and do not create independently enforceable requirements.", "jurisdiction": "US" } ```