Crews were cleaning propane trucks at a business in West Point Wednesday afternoon when the blasts and fire happened.
Witnesses say the workers were taken to the hospital on a medical helicopter after seven of them had originally been transported to St. Francis Memorial Hospital in West Point.
It took about 30 minutes for fire crews to bring the blaze under control.
A woman living nearby says she heard an initial blast, then several more at about 3:30 p-m Wednesday.
The accident took place at Sapp Brothers Petroleum in West Point.