CROSBY, Texas — The explosion at the KMCO chemical plant in Crosby happened when a transfer line ignited a tank full of a chemical called isobutylene, according to Harris County Sheriff Ed Gonzalez.

The fire spread to a warehouse containing other combustibles, but it’s not clear yet what kind. One person was killed and two people were badly injured.

RELATED: LIVE COVERAGE: One person dead; shelter-in- place for nearby residents after Crosby chemical plant fire

Isobutylene is a highly flammable colorless gas that can cause a faint petroleum-like odor, according to the National Oceanic and Atmospheric Administration.

If inhaled, it can cause dizziness, drowsiness and unconsciousness. Contact with eyes or skin can cause irritation.

First Aid

INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. If symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop, call a physician and be prepared to transport the victim to a hospital. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used; if not available, use a level of protection greater than or equal to that advised under Protective Clothing.

EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.

SKIN: Exposure of skin to compressed gases may result in freezing of the skin. Treatment for frostbite may be necessary. Remove the victim from the source of contamination. IMMEDIATELY wash affected areas gently with COLD water (and soap, if necessary) while removing and isolating all contaminated clothing. Dry carefully with clean, soft towels. If symptoms such as inflammation or irritation develop, IMMEDIATELY call a physician or go to a hospital for treatment.

RELATED: KMCO was criminally convicted of violating Clean Air Act in 2016