The blast was the fourth at the 640-acre Phillips chemical complex in the past year.
Rodney Gott, the 45-year-old supervisor in the K-Resin plant was the one person killed Monday afternoon. Seventy-four other workers suffered injuries, according to The Houston Chronicle.
Gott had worked for Phillips for 19 years and survived a devastating explosion at the plant in 1989 that killed 23 workers.
Phillips Pasadena plant has a history of safety problems and accidents.
OSHA fined Phillips $204,000 for violations after an explosion killed two workers and injured four others in the same plant on June 23, 1999.
OSHA, along with the federal Bureau of Alcohol, Tobacco and Firearms, are participating in the investigation of this week's explosion.
Officials said they were not sure whether Monday's explosion occurred at, or near, the same K-Resin reactor as the June explosion. The plant has four reactors.
"Our safety people have been in there most of the day and just now are letting people in to take a look," said Jere Smith, a Phillips spokesman.
Smith said it may be a couple of months before the cause of the 1:22 p.m. blast can be determined.
Ray Skinner, area director for OSHA's Houston South division, said investigators who are examining the blast site will also take information from workers and others into account.
"We're hearing a lot of information," said Skinner, declining to elaborate.
Monday's explosion forced Phillips officials to halt operations at the Pasadena complex.
Plant officials Tuesday were inspecting the polyethylene and polypropylene sections to determine whether they were safe to resume operations.
Those sections are expected to be up and running by the end of this week.
Phillips officials said anyone with questions about the explosion, or who want to make a claim can call (800) 766-6362 or file claims on-line at www.phillips66.com/hcc/claims.