Commonly Encountered Mercury (continued)

Visual	Description of Item	Mailability of Item
	Liquid mercury — Often encountered in a wide range of volumes. Reasons for sending include uses for gold reclamation or refinement, preparation of dental amalgams, and element collections.	Domestic Ground – Prohibited Domestic Air – Prohibited International – Prohibited Prohibited per section 348.21e.
	Mercury barometer — These devices often contain significant amounts of mercury that are not well contained. They have been responsible for several leaks. (Note: Fully digital versions are mailable without restrictions.)	Domestic Ground – Prohibited Domestic Air – Prohibited International – Prohibited Prohibited per section 348.21e.
	Mercury thermometer — These items may contain significant amounts of mercury in breakable containment (glass). [Modern versions (i.e., digital and those using red liquid — which is alcohol to which red coloring has been added) are mailable without restrictions.]	Domestic Ground – Prohibited Domestic Air – Prohibited International – Prohibited Prohibited per section 348.21e.
	Mercury sphygmomanometer (blood pressure gauge) — These devices may contain significant amounts of mercury in breakable containment (glass). (Note: Fully digital versions are mailable without restrictions.)	Domestic Ground – Prohibited Domestic Air – Prohibited International – Prohibited Prohibited per section 348.21e.
	Mercury switch — These items may exist in a small enough size to get below the 100 mg. limit; however, this would be the exception rather than the rule. If you can see the mercury, it is not mailable.	Domestic Ground – Prohibited Domestic Air – Prohibited International – Prohibited Prohibited per section 348.21e. May encounter some per section 348.22g.
	Mercury relay — These items may exist in a small enough size to get below the 100 mg. limit; however, this would be the exception rather than the rule. If you can see the mercury, it is not mailable.	Domestic Ground – Prohibited Domestic Air – Prohibited International – Prohibited Prohibited per section 348.21e. May encounter some per section 348.22g.
	Compact fluorescent lamps — These items contain small amounts of mercury vapor. If broken, there will be no visible mercury and the vapors will readily disperse.	Domestic Ground – Mailable Domestic Air – Mailable International – Prohibited Mailable per section 348.22g. See also Packaging Instruction 8C.

USPS^® is committed to the safety and security of its employees, customers, and transportation networks. We must remain vigilant in safeguarding the mailstream against any article that might pose a hazard to health, safety, property, or the environment.

If a person knowingly mails items or materials that are dangerous or injurious to life, health, or property, they may face a civil penalty of at least $250, but not more than $100,000 per violation; the costs of any cleanup associated with each violation, and damages. They may also face criminal penalties.

— Product Safety,
Product Classification Product Solutions, 7-11-2024