SAUGET/EAST ST. LOUIS – Shortly after 12:44 a.m. Wednesday, Aug. 12, 2026, emergency responders from multiple counties were called to a reported chemical fire at a facility along Sauget Industrial Drive in Sauget, Illinois, where officials later identified the hazardous material involved as trichloroisocyanuric acid and issued shelter-in-place notifications because of a visible chemical plume.
St. Clair County Emergency Management Agency Director Herb Simmons said the response quickly developed into a significant hazardous-materials incident requiring personnel, specialized equipment and resources from throughout the region.
More than 50 first responders representing more than a dozen departments and agencies from St. Clair, Madison, Monroe and other counties responded. Among them were members of the St. Clair County Special Emergency Services Association, including hazardous-materials technicians trained and equipped for dangerous environments.
Simmons said he was asked by the Sauget incident commander and the chief of Special Emergency Services to handle public information officer responsibilities during the incident.
“One of the most important responsibilities during an incident involving hazardous materials is determining whether the incident poses a threat beyond the immediate scene,” Simmons said.
As the fire continued, Simmons said, a large chemical plume was visible, and emergency officials evaluated conditions and the direction of the plume. Based on those conditions, a shelter-in-place notification was issued for the potentially affected area.
The St. Clair County Emergency Alert notification system was used to notify people within the designated geographical area. Residents and businesses were instructed to remain indoors, close windows and doors, and turn off or avoid using systems that bring outside air into homes or businesses. East St. Louis School District 189 postponed classes after the stay-in-place order was issued.
Simmons said the shelter-in-place area was adjusted and expanded as conditions changed and the plume moved.
“These boundaries were not selected at random,” Simmons said. “Emergency personnel were monitoring the situation and adjusting the protective area based upon the conditions being encountered and the direction the plume was traveling.”
Simmons said the incident was complicated because trichloroisocyanuric acid can irritate the skin, eyes and respiratory system and is reactive with water. Firefighters and hazardous-materials technicians had to address the fire, the plume and water runoff generated during firefighting operations.
Approximately 10 tandem loads of sand were requested so responders could construct a berm to isolate and mitigate runoff, Simmons said.
“This was much more complicated than simply putting water on a fire,” Simmons said.
Simmons said incident commanders and hazardous-materials personnel evaluated the chemical involved, the plume, runoff, changing conditions, and potential exposure to responders and the surrounding community while emergency management coordinated public notifications and information.
He said more than 50 responders worked together during the incident, including firefighters, hazardous-materials technicians, law enforcement officers, emergency management personnel, dispatchers, highway personnel and other supporting agencies and organizations.
“The fact that an incident involving fire, hazardous chemicals and a significant plume could be handled without injuries to the responding personnel speaks volumes about the training, planning and professionalism of everyone involved,” Simmons said.
Simmons also thanked news media members, residents and businesses in the shelter-in-place area, and people who followed agency updates on social media.
“These decisions are never made lightly,” Simmons said of the protective actions. “They are made based upon the information available at that particular time and with one overriding consideration: The safety of the public.”
