On April 8, 2025, PHMSA announced updates to their Letter of Interpretation (LOI) request process. In an effort to be more transparent in the LOI review process, PHMSA has now created a Pending Hazardous Materials Interpretation link from their Letters of Interpretation web page. Once a LOI request is received and processed, the request will be posted to the “pending” website for 30 days. During that time, the public will be able to review and comment on the request before PHMSA makes a final decision on the response. This will provide transparency into the review process and allow PHMSA to solicit feedback on requests.

Key items:

  • PHMSA is NOT changing how to request a LOI, nor are they changing how to search for an LOI.
  • Pending LOI requests will remain for 30 days before being removed.
  • Comments received will NOT be shared with the public or published on the website or related docket.
  • PHMSA will conduct an initial review of the request before posting to the Pending LOI site.
  • Due to the public nature of the site, submitters are requested to provide redacted copies if the request contains confidential information.
  • The website will “go live” within the next week. Until then there are sample letters of interpretation (No. 25-1004, 25-1007, 25-1012) that are posted ONLY AS EXAMPLES to demonstrate the process. These LOIs have already been issued and are not pending.

Those interested in being notified of new postings to the Pending LOI site may sign up for Email Alerts directly through PHMSA.