Theories Emerge in Texas Blast

Questions have arisen about Texas' inspection level for the West fertilizer plant that exploded last week, killing 14 people.

According to a Houston Chronicle report, Gov. Rick Perry has defended the state's inspection process.

However, the Occupational Safety and Health Administration, which oversees workplace safety, last inspected the plant in 1985, according to the news report.

Though an investigation is underway, the report said it could take weeks to determine a cause of the initial fire.

Early forensic results produce a few theories for the fire's origin, one possibly being a rail car that served as a storage tank holding ammonia.

Another theory is the amount of stored chemicals, like excessive amounts of Anhydrous ammonia.