Is a convenience store that sells alcohol to a minor liable for injuries caused when the minor, drunk and driving, injures or kills another? The answer is likely "yes." I had an interesting call about such a fact pattern and did a little research to find a similar fact pattern, and there are plenty of them out there.
Generally, a store that sells alcohol has a duty to check identification of the buyer. If the store breaches that duty by failing to check, and sells alcohol to a minor, there is potential liability for the seller. If the seller routinely fails to check identification that liability could include additional damages to someone injured by the purchaser.
In one case I know of, a minor who purchased alcohol from a convenience store collided with another car, resulting in his death. His survivors brought a lawsuit against the store, and showed that the store (which videotaped sales) had a practice of selling beer to minors without checking for identification. The case settled because it was clear that the duty owed to the public had been breached, resulting in the wrongful death of the minor.
The answer to this problem should be simple enough – store employees simply need to insure that they sell alcohol only to adults.