An explosion at the Houston Chemical Complex in Pasadena, Texas, which registered a 3.5 on the Richter magnitude scale, kills 23 and injures 314.

On 23 October 1989 at approximately 1:05 PM Central Daylight Time, a series of explosions occurred at Phillips Petroleum Company's Houston Chemical Complex (HCC) in Pasadena, Texas, near the Houston Ship Channel. The initial blast registered 3.5 on the Richter scale, and the resulting fires took 10 hours to bring under control, as efforts to battle the fire were hindered due to damaged water pipes for the fire hydrants from the blast. The initial explosion was found to have resulted from a release of extremely flammable process gasses used to produce high-density polyethylene, a plastic used for various consumer food container products. The US Occupational Safety and Health Administration fined Phillips Petroleum Company $5,666,200 and fined Fish Engineering and Construction, Inc., the maintenance contractor, $729,600. The event killed 23 employees and injured 314.

Pasadena is a city in the U.S. state of Texas, located in Harris County. It is part of the Houston–The Woodlands–Sugar Land metropolitan area. As of the 2020 U.S. census, the city's population was 151,950, making it the 23rd most populous city in Texas and the second most populous in Harris County, after Houston. The area was founded in 1893 by John H. Burnett of Galveston, who named the area after Pasadena, California, because of the perceived lush vegetation.

The Richter scale, also called the Richter magnitude scale, Richter's magnitude scale, and the Gutenberg–Richter scale, is a measure of the strength of earthquakes, developed by Charles Richter in collaboration with Beno Gutenberg, and presented in Richter's landmark 1935 paper, where he called it the "magnitude scale". This was later revised and renamed the local magnitude scale, denoted as ML or M_L .

October 23 is the 296th day of the year in the Gregorian calendar; 69 days remain until the end of the year.