EMBED >More News Videos In this viewer-submitted video, flames and heavy smoke are seen in a huge four-alarm fire in Spring Branch

EMBED >More News Videos Fireballs swallowed a business in Spring Branch.

HOUSTON (KTRK) -- A massive fire destroyed a warehouse in northwest Houston Thursday and now residents are now being cautioned to avoid the water run-off nearby.Explosions sent flames into the air around 10am from A-1 Custom Packaging on Spring Branch Drive at Laverne Street. No one was injured in the huge fire, but several neighboring homes and vehicles suffered heavy damage.Spokesman Ruy Lozano with the Houston Fire Department says pesticides and a petroleum additive frequently used in diesel got into drainage ditches behind the warehouse. Environmental crews are vacuuming the non-water-soluble additive out of a nearby creek, but the bigger danger lies in the pesticide, which is water soluble and already in the ditches and in Spring Branch Creek.Officials hope the recent floods will dilute the pesticides enough to where they're no longer harmful.Firefighters are warning families to stay away from ditches in the area. For pet owners, that means keeping your animals indoors and away from the water."They had us turn off our A/Cs. The concern now is going to be with us they said breathing and stuff, so they want our A/C off and they want us to wash off just because the HazMat stuff," nearby resident Willy Gonzalez said.HFD does not know how many people have wells in the area, but anyone who does is encouraged to get theirs tested."Any time you have fire like this one that is petroleum based, that's solvent, you have the potential for rekindle. You put it out, and it will come right back," Lozano said. "That's why if you noticed they weren't just flowing water out of those aerial apparatuses, they were flowing foam."Joe Yarborough said he built the now-destroyed warehouse in 1987 and has rented it out to a company called Custom Packaging for the last 18 years.He said the company repackages large amounts of chemicals into small containers."Like horse spray, that you spray a horse with to keep the bugs off of it," Yarborough said, "it will come in in a tanker truck, they'll repackage it into like 6-8 ounce bottles and then ship it out for the manufacturer."Yarborough does not know what other chemicals were inside, and neither do firefighters at this point.Yarborough thinks the fire started at a home and spread to the warehouse. That's under investigation.For now, Yarborough is hoping for the best."Get the adjuster to come out, see what HazMat says. I don't know what all they had down there," he said.Until we know for sure, firefighters want all families nearby to stay away from the runoff.