The San Angelo Standard-Times reported Tuesday that it's unclear how close the victims were to the 20-foot high tank, which exploded Monday.
A woman answering the phone Tuesday at SNS Steel Industries LLC in San Angelo, who declined to give her name, said the company had no comment.
Fire department Capt. Fred Barnett says the workers were pressure testing a tank that had been built when the equipment broke loose and exploded.
Barnett says three people were transported to a hospital. Further details on their conditions and their names were not immediately released.