Legal Status of Special Permits for Use of Composite Cylinders
Pipeline and Hazardous Materials Safety Administration · Apr 28, 2008 · Reference No. 08-0109
Interprets: 49 CFR § 107.305, 49 CFR § 107.307, 49 CFR § 107.333
Reggie’s quick take
Someone asked PHMSA for a summary of the legal status of DOT Special Permits covering the making, marking, selling, and using of composite gas cylinders. The agency's answer is that a Special Permit has the same legal force as a DOT regulation published in the Code of Federal Regulations. Compliance inspections and penalties apply the same way to both, under 49 CFR 107.305, 107.307, and 107.333. A Special Permit may set alternative packaging or practices, but PHMSA must find it keeps safety at least equal to the general rule. Issuing one also requires a public comment period.
Written by AI (Claude) on Oct 22, 2026. Robots make mistakes and leave things out, so the letter below is what counts. Not legal advice.
This is in response to your letter of March 20, 2008, asking for a summary of the legal status of DOT Special Permits for the manufacture, marking, sale, and use of composite cylinders for compressed gases.
The United States Department of Transportation (DOT) issues hazardous materials transportation regulations (HMRs) under the authority of Title 49, United States Code, Sections 5101, et seq. Under this law, HMRs of general applicability are published in title 49 of the United States Code of Federal Regulations (CFR) Parts 100-185. These regulations have the status of law, and are enforceable by compliance orders as well as civil and criminal penalties. The HMRs include a number of gas cylinder specifications in 49 CFR Part 178, and makers of this hazardous materials packaging are subject to DOT's direct inspection and enforcement jurisdiction.
In addition to the regulations of general applicability, 49 USC. § 5117 empowers the Secretary of Transportation to issue Special Permits authorizing alternative practices and packaging to those specified in the general HMRs. The application and grant process has been delegated to the Pipeline and Hazardous Materials Safety Administration (PHMSA) and is described in 49 CFR Part 107, Subpart B. PHMSA must find that the Special Permit maintains a level of safety "at least equal to the safety level required" under the regulations of general applicability. As required for establishment of a general regulation such as a specification for packaging, issuance of a Special Permit is a public process, involving a public comment period. DOT maintains several thousand Special Permits, many prescribing equivalent standards for the manufacture and use of composite cylinders.
Regulations of general applicability and Special Permits are legal authorizations developed, issued, and enforced by PHMSA. Compliance inspections and sanctions apply equally, whether a matter is covered by a general regulation or a Special Permit. See 49 CFR Subpart D, Sections 107.305, 107.307, and 107.333. Thus, a Special Permit has the same legal force and effect as a DOT regulation published in Title 49 Code of Federal Regulations, and is considered equivalent to the specifications.
If you have additional questions please contact me at 202-366-4511.
A letter of interpretation applies the regulations to the facts the requester described. It isn’t a regulation and isn’t legal advice. The agency’s copy.