Is frozen salmon ok to eat if left out for 4 hours and is still hard and cold?

If frozen salmon has been left out for 4 hours but remains hard and cold, it may still be safe to eat. However, it's essential to consider that the outer layer could be at a temperature that allows bacterial growth. To ensure safety, it's best to thaw salmon in the refrigerator or under cold running water, rather than leaving it out at room temperature. If in doubt, it's safer to discard it.