What changed

PHMSA finalized HM-126F update on March 1, 2026 tightening 49 CFR §172.704 security awareness training requirements for hazmat employees. The 36-month refresher cycle is now hard-coded - previously the rule allowed "as the employer determines" frequency, which had drifted toward "rarely" at smaller carriers.

The training topics covered under §172.704(a)(4) - recognizing security risks, enhancing security culture, and recognizing and responding to potential security threats - must be documented in the hazmat employee's training record with date, instructor signature, and a brief topic outline.

Who this affects

Every CDL holder with an H (hazardous materials) endorsement and every dispatcher, loader, or warehouseman who handles placardable hazmat is subject to the rule. The 36-month cycle starts from the most recent training date - many carriers will need to compress their next refresher to land within the new window.

Documentation requirements

Each hazmat employee's training record must include the date training was completed, a description of the topics covered, and the signature of the instructor. Records must be retained for 90 days following the employee's last hazmat-handling activity.

Carriers using a third-party LMS (learning management system) like Inthinc, JJ Keller Training, or Fleetio should verify the LMS is generating §172.704-compliant records. Some legacy LMS modules cover the topics but do not produce the §172.704 record format.

What to do next

Audit your hazmat employee training records. Identify any worker whose most recent §172.704 training is older than 33 months - schedule the refresher before the 36-month cliff. Our /guides/hazmat-endorsement-requirements page covers the full hazmat regulatory framework.