A 3-year-old boy was the fourth victim killed in a massive illegal fireworks explosion in Hawaii, succumbing to injuries Jan. 6. The blast also killed three women and seriously injured more than 20 others.

The six victims are in their 20s and 30s, and all have extensive burns, according to Dr. Kevin Foster, director of the Arizona Burn Center.

Six survivors of a massive fireworks explosion in Hawaii have been flown to Phoenix for treatment. This comes as we're learning a three-year-old boy died on Monday as a result of the blast, raising the death toll to four.