The fire at a plastics feedstocks plant operated by Shell Chemical in Deer Park, Texas, was extinguished late on May 9, four days after it first broke out.
As a result, officials said, responders are using less water to manage hot spots, and runoff water discharge is no longer being directed to the Houston Ship Channel. Water continues to be added to nearby retention ponds to cool equipment.
Air monitoring is ongoing and Shell has not detected harmful levels of chemicals affecting neighboring communities. Officials said residents may continue to see intermittent flaring from the facility.
No major injuries have been reported from the fire, although nine contract employees were treated for exposure to chemicals. The fire started around 3 p.m. May 5 while an olefins unit was undergoing routine maintenance, they added. The fire ignited cracked heavy gas oil, cracked light gas oil and gasoline.
Officials said the fire was extinguished May 7, but it reignited later that day. They said late on May 7 that the re-ignited fire had been contained to a controlled zone.
As a precaution, a boom was deployed to prevent any product from entering the channel.
Shell officials said earlier that air monitoring is ongoing and hasn't detected any harmful levels of chemicals affecting neighboring communities. No evacuation or shelter in place orders were issued.
"There is no danger to the nearby community, however residents and neighbors may notice black smoke, flaring and increased noise from the facility," they added. "Our immediate priorities remain the safety of people and the environment."
The cause of the fire will be the subject of a future investigation. Shell makes a wide range of chemicals at Deer Park, including olefins ethylene and propylene. The site also makes butylenes, phenol and acetone that are used in plastics production.