PHMSA and the U.S. Postal Service collaborated on a set of safety guidelines for those wanting to mail lithium batteries. Persons wishing to ship lithium batteries and electronic devices containing lithium batteries should be aware that certain requirements must be met to ensure safety. Both agencies are responsible for enforcing the safety standards regarding the appropriate labeling and shipment of hazardous materials under PHMSA's Hazardous Materials Regulations for the safe transportation of lithium batteries in commerce.