HOUSTON (AP) — A fire official says about 500 gallons of pesticides were stored at a Houston warehouse complex consumed by a large blaze and authorities are trying to determine how much ran off into nearby creeks.

Fire Capt. Ruy Lozano said Friday that it's not clear how much of the pesticide was burned in the fire and how much leaked into adjacent waterways.

The fire Thursday morning began in a home and spread to the nearby warehouse complex.

Petroleum additives also were stored at the complex and the chemicals fueled the blaze and caused thick billowing smoke that could be seen for miles.

Lozano says the remains of the fire are still creating smoke that could prove harmful if inhaled, so people are being asked to stay away from the area.