1.1.1 Site Description  At 0837 hours on 13 June 2013, there was an explosion and fire at the Williams Olefins Geismar plant. As of 1700, Williams reported approximately 73 workers were injured and one fatality due to the explosion and subsequent fire. After the explosion, part of the plant continued to burn for several hours. Williams on-site response personnel fought and controlled the fire.  The fire was extinguished by early afternoon, but the plant was without power and material (primarily propylene) within the process piping continued to vent to one of the plant flares where the material was partially combusted. The partial combustion was due to the inability to power air blowers and steam valves at the flare. As a result, a thick black smoke was produced, raising concerns for downwind residents and businesses. Many roads were closed near the facility, including LA Hwy 30 and LA Hwy 3115. LA Hwy 30 was reopened at approximately 1600 hours. Overnight the only remaining road closure was LA Hwy 3115 from LA Hwy 30 to LA Hwy 75 (River Road). Shelter-in-place orders were issued for surrounding plants, but were all lifted by 1800 hours on 13 June.

1.1.1.1 Location  The Williams Olefin Geismar plant is located on Louisiana Hwy 3115 near Geismar, in Ascension and Iberville Parishes, Louisiana. The plant is located in an industrial area. The nearest residences are located approximately 2.5 miles northeast of the facility.

1.1.1.2 Description of Threat  The Williams Olefins Geismar plant converted ethane to ethylene and propylene. The main chemicals on site were ethane, ethylene, propane, propylene, and butadiene. Some materials may have been released during the explosion and fire. The plant shut off valves to all units, but materials in the process piping, believed to be mostly propylene, continue to be vented through the facility flare. The explosion knocked out electricity at the facility, so the flare was not operating efficiently for much of the day resulting in a large plume of black smoke. By 1800 hours on June 13, some electricity had been restored to the flare, allowing the operation of fans which increased the combustion efficiency and eliminated most of the smoke.

Damage to a flange-pipe near the explosion site caused the extended release of small amounts of propylene into the air. Plant officials were unable to safely address the release due to uncertainty about structural stability in the blast area. In order to reduce the release to the air, personnel were positioned with a fire hose to continuously douse the flange with water. Plant officials conducted air monitoring inside of the plant near the damaged flange.

The nearest residents are located approximately 2.5 miles northeast of the facility. LDEQ and EPA conducted off-site air monitoring and air sampling in the neighborhoods downwind of the facility, but detected no readings above background.

Firefighting water was not contained on the facility due to the excessive amount of water utilized and the lack of electrical power to operate lift pumps within the plant drainage sumps.  Firefighting water and potentially process water, was released into drainage ditches leading offsite.  EPA measured the pH of the water in the drainage ditch on 13 June 2012 and found that it was 5-6, and no sheen was noted.