The suit, first discussed in September, claims the plant's explosion after Harvey caused negative health effects to residents nearby.
A criminal investigation is also underway, Harris County District Attorney Kim Ogg told ABC13 in September.
"Companies should be on notice that we care when they pollute our air, our water, our environment," Ogg said. "We are looking into exactly what happened at the plant. We are gathering facts and we will apply the law. Arkema is under criminal investigation."
RELATED: First responders sue Arkema after becoming ill
Thursday's suit alleges Arkema had unpermitted air releases, wastewater releases, violated the Clean Air Act and asks for reimbursement for costs incurred by the county during the enforcement of the 1.5-mile evacuation zone. It also asks for an "environmental audit" of the Arkema plant to find out what it will take to "bring the Facility into compliance."
Additionally, the county alleges that because the facility is in a floodplain, any buildings must have a permit under floodplain regulations. County records show Arkema doesn't have a permit for one or more of the structures on the property, the suit alleges.
"This was a very dangerous situation," County Attorney Vince Ryan said in an e-mailed statement. "Arkema must take responsibility for its inability to ensure the safety of the people of the Crosby community and those who protect them."
Arkema's Houston attorney Rusty Hardin says Arkema is the victim.
"Suing a victim is never the right solution to a natural disaster," Hardin said. "We are disappointed that this lawsuit was filed when we were in discussions with the county to cooperatively resolve the issues. As they and we all know, this was an extraordinary flooding event. Arkema and its employees, like other businesses and individuals in Harris County, were victims of this storm. Our plant is still not open. Our employees are still not back to work. Filing lawsuits is not the solution here. Arkema plans to continue cooperating with authorities, but we will strenuously defend against any and all unfounded claims."
Wednesday, members of the Chemical Safety Board questioned Arkema's safety plans after building the plant in a flood zone and not having a disaster plan that included the possibility of significant flooding.
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