christina gonzalez, what have they been telling you? >> reporter: the injuries were minor. these people got checked out of the hospital with minor injuries. when you are looking at this kind of damage, look at this. from sky fox, looks like a bomb went off at one of the processing units of the exxon refinery in torrance. they have let to figure out what caused the explosion. employees say it began with a smell. >> i smelled chemical smell at first. i went and looked and didn't see anybody evacuated so i went back to the electrical room. >> reporter: half an hour later. >> i heard a blast. a very large blast. an explosion. and my whole area shook. >> reporter: according to cal tech, it created shockways equal to a 1.7 earthquake in the area. >> right away you think earthquake? >> it could have been an earthquake, nope, it's the factory. >> reporter: the exxon refinery. >> we found there was still some active fluid on the ground. as a result of the explosion, the fluid, gasoline, it was oneover the processing units. there was a resulting ground fire that occurred momentarily.