To prevent children from injuring themselves with firearms.

Prohibits a person from leaving a loaded firearm, or an unloaded firearm and ammunition, any of which has been shipped or transported in interstate or foreign commerce, in a manner that the person knows or reasonably should know is likely to be accessible to a juvenile, unless the person has given the juvenile permission to possess the firearm and the possession is under the supervision of an adult who is not prohibited by Federal, State, or local law from possessing a firearm. Requires that: (1) licensed dealers post a copy of such prohibition; and (2) notice be included on the form required to be obtained by licensed dealers from prospective firearms transferees. Makes it an affirmative defense that the firearm was left in a locked, opaque box or with a trigger locking device installed. Directs the Secretary of the Treasury, after notice and opportunity for a hearing, to impose a civil penalty of up to $1,000 for a violation. Limits judicial review of the Secretary's action.

Prohibits, with exceptions, the sale of a firearm by a licensed dealer to any person unless, before the sale, the dealer has offered to sell the purchaser a trigger locking device, explained its operation, and had the person indicate in writing that the person understands that trigger locking devices are available for purchase.