WASHINGTON — As millions of Americans prepare to mark the nation’s 250th birthday with backyard fireworks this weekend, federal safety regulators are urging caution after a sharp rise in injuries and deaths last year. Fireworks sent an estimated 13,000 people to emergency rooms in 2025 and killed 15, according to the U.S. Consumer Product Safety Commission. The year before was even worse, with 14,700 injuries and 11 deaths in 2024, a 52% jump in injuries and a 38% rise in fatalities from 2023.