April 8, 2019

Mailing Requirements for Mailing Parcels Containing Mercury

In response to a recent spill of metallic mercury in our Postal network, it is important that our employees and customers are aware of the mailing requirements related to the mailability of parcels containing mercury and the potential hazards of a mercury spill. Due to the nature of this material and its potential for producing toxic effects, these spills represent a tremendous safety risk to our employees and customers as the liquid form of mercury vaporizes at room temperature and can be inhaled and easily absorbed by the body. Additionally, the cleanup process for such spills are both laborious and costly. In each case where spills have occurred, the affected facility incurred excessive down time at great cost to Postal Service.

Devices containing enough mercury to be seen with the naked eye are nonmailable. This includes items containing mercury metal (especially antique items), such as thermometers, barometers, blood pressure meters and similar devices. This would generally not include newer types of these devices, especially digital versions.

These types of devices that contain mercury should not be confused with manufactured devices that contain small amounts of mercury (UN3506). UN3506 devices include Compact Fluorescent Lamps (CFL), fluorescent tubes and similar consumer devices containing minute amounts of mercury. These items are mailable by air or surface only when each device, article, or apparatus contains 100 milligrams (mg) (0.0035 ounce) or less of mercury (less than a grain of salt) and each mailpiece contains no more than 1 gram (g) (0.035 ounce) of mercury. Mercury contained in devices categorized under UN3506 typically exists in a vaporized state - no metallic mercury will be visible in UN3506 devices. See Publication 52, section 348.22, Packaging Instruction 8C in Appendix C, and Postal Bulletin 22516, March 28, 2019, page 45 for details.