HEMEL HEMPSTEAD, England Explosions ripped through a major fuel depot north of London on Sunday, injuring dozens of people, blowing doors off nearby homes and sending fireballs and massive clouds of black smoke into the sky.

Police said the blasts appeared to be accidental, though they occurred just four days after an al-Qaida videotape appeared on the Internet calling for attacks on facilities carrying oil "stolen" from Muslims in the Middle East.