Lithium Battery Contained in Equipment
Pipeline and Hazardous Materials Safety Administration · Nov 7, 2022 · Reference No. 22-0102
Interprets: 49 CFR § 173.185(b)(2)(iii)
Reggie’s quick take
A company that packs a portable hearing-test headset asked whether its packing method meets the accidental-activation rule in § 173.185(b)(2)(iii). The headset has a lithium polymer cell under 20 Wh, is placed in "factory shipping mode," and is packed in a hard Pelican case. The agency said yes: the packing as described complies with § 173.185(b)(2)(iii). The same answer applies to the small coin cell in the headset's clock, which draws a tiny current in that mode.
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.
November 7, 2022
Reference No. 22-0102
This letter is in response to your September 23, 2022, email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to a lithium battery contained in equipment. Specifically, you state that your client ships a portable headset for hearing tests that is packed in a hard-shell impact resistant Pelican™ case. You also state that the portable headset is powered by a lithium polymer cell that is less than 20 Watt-hours (Wh) and—to prevent accidental activation of the equipment—the device uses a power management integrated circuit placed in “factory shipping mode” which prevents any electrical current from being drawn from the cell except for a very small electrical current of 0.23 microamps (µA) . You further note that pressing the power button while in “factory shipping mode” has no effect on the device, and the portable headset can only be turned on and activated if a USB charging cable. Therefore, you ask whether the packing method of the portable headset—as described—would comply with the requirements of 173.185(b)(2)(iii) to prevent accidental activation of the equipment.
Additionally, you state the portable headset also contains a real-time clock that is powered by a small, non-rechargeable coin cell battery with a lithium content that is less than 0.1 grams. When the portable headset is shipped in “factory shipping mode,” the real-time clock draws a small electrical current of 0.67 µA to keep track of time. You ask whether this would satisfy the requirements of 173.185(b)(2)(iii) as well.
Based on the information you have provided; it is the opinion of this Office that the manner of packing as described for both scenarios would comply with the requirements of 173.185(b)(2)(iii) for prevention of accidental activation of the equipment.
I hope this information is helpful. Please contact us if we can be of further assistance.
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.