What are ethylene and propylene, the chemicals released in the INEOS pipeline explosion in Brazoria County?

Erica Ponder, Digital Content Producer

BRAZORIA COUNTY, Texas – Massive flames erupted in Brazoria County Thursday due to a chemical release in pipelines at a remote valve site, a spokesperson for the company INEOS said.

According to INEOS, ethylene and propylene gases were released in the pipelines, but what are they? KPRC 2 researched the chemicals:

Ethylene is the simplest of the organic compounds known as alkenes, which contain carbon-carbon double bonds.

According to Brittanica, it is a colorless, flammable gas that has a sweet taste and odor. Natural sources of ethylene include both natural gas and petroleum. It is also a naturally occurring hormone in plants, which inhibits growth and promotes leaf fall, and in fruits, which promotes ripening.

Ethylene is known as an important industrial organic chemical. According to the National Library of Medicine, it is easily ignited. It’s not toxic but it is considered to be a simple asphyxiant.

Propylene, also called propene, is a colorless, flammable, gaseous hydrocarbon obtained from petroleum.

According to Brittanica, large amounts of propylene are used in the manufacture of resins, fibers, and elastomers, as well as several other chemical products.

Propylene has a faint petroleum-like odor. Contact with the liquid can cause frostbite, according to the National Library of Medicine. It is easily ignited and the vapors are reportedly heavier than air. Under prolonged exposure to fire or intense heat, containers that have propylene may rupture violently and rocket. The chemical can cause an explosion.

Officials said the actual cause of the fire is undetermined at this time. An air monitoring crew is in the area.

BRAZORIA COUNTY, Texas