Responding to what it called “criminal levels” of contamination, the Harris County District Attorney’s office said Monday that it has charged Intercontinental Terminals Company with five misdemeanor counts of water pollution arising from a March plant fire that sent toxic chemicals into nearby waterways and a thick plume of smoke over the Houston area for days.

“The discharge from the ITC fire into Tucker Bayou is a clear water pollution case,” said Alex Forrest, the environmental crimes division chief for the DA’s office, in a written statement. “We are looking forward to reviewing the reports of other local and federal agencies, as they complete their investigations, so that we can determine if other charges will follow.”

The charges are the most recent example of District Attorney Kim Ogg’s more aggressive approach toward chemical companies in the aftermath of environmental disasters that have outraged the public and drawn national attention.

“This is the beginning of our review, not the end,” said Dane Schiller, a spokesman for the DA’s office.

According to the DA’s Office, water pollution in Tucker Bayou was at “criminal levels” from March 17 through March 21. Prosecutors filed one count for each of the five days the company allegedly violated the law at its Deer Park plant. Each charge carries a fine of up to $100,000.

“People living in Deer Park and the other neighboring residential areas near ITC’s plant deserve protection,” Ogg said. “When public health is at risk, it’s a public safety concern.”

An attorney for ITC, which stores petrochemicals for companies including Chevron, Philips 66 and Exxon, defended its efforts.

“Although we have not seen the charges, there is no question that there was a large fire and an enormous effort to extinguish it which resulted in a discharge into Tucker Bayou,” said Michael Goldberg, an attorney for ITC, in a written statement.

The Deer Park blaze began when a leak at one of ITC’s petrochemical storage tanks caught fire on March 17. The conflagration created a thick plume of toxic smoke and chemicals that blanketed parts of greater Houston. During the days-long disaster, a containment wall breached, pouring large amounts of toxic chemicals such as xylene and benzene into Tucker Bayou. The blaze and spills led neighborhoods and schools to “shelter in place,” prompted a temporary closure of the Houston Ship Channel, and raised fears about air and water quality throughout the metro area.

More than two weeks later, one worker was killed and two others were critically wounded during a fire at KMCO’s Crosby chemical plant. State officials have filed lawsuits against ITC as well as KMCO in Crosby for pollution caused by fires at both facilities.

ITC also faces a blizzard of lawsuits filed by area residents in the aftermath of its fire, which destroyed 11 chemical tanks and is under investigation by the U.S. Chemical Safety Board, the Environmental Protection Agency and the Texas Commission on Environmental Quality.

Harris County officials previously estimated that its response to the disaster cost approximately $1.9 million in services, materials, supplies and labor.

Monday’s court action against ITC marks the second time Ogg has pursued criminal charges against Houston-area companies in high-profile pollution cases. After a chemical fire during Hurricane Harvey in 2017, Ogg brought a criminal case against the chemical company Arkema and two of its executives for the “reckless” release of an air contaminant.

Investigators found that the company’s emergency plan provided little direction to employees on how to handle major floods, and as a result, it couldn’t keep combustible organic peroxides cool, according to federal documents. Over the next week, nine trailers of organic peroxides erupted in flames, sending pillars of fire and thick plumes of black smoke into the air.

Prosecutors recently charged the company and a third executive with reckless assault, citing injuries sustained by two deputies who responded to the scene based on the company’s assurances. Company officials have defended their actions in both suits and accused Ogg’s office of prosecutorial overreach.

A fire also broke out at Exxon Mobil’s Baytown refinery in mid-March but was contained hours later. The investigations are ongoing.

Luke Metzger, executive director of Environment Texas, a state advocacy group, said Monday’s charges send an important message to companies.

“It really raises the bar for industrial facilities,” Metzger said.

Harris County has stepped up oversight of the petrochemical industry since Ogg took office in 2016, and the 2018 election brought in new Democratic leadership on the Commissioners Court.

Ogg’s office recently called for an additional $850,000 to fund eight new positions in the environmental crimes division, including tripling the number of prosecutors — from two to six — focused on such violations.

That’s a change, Metzger said, adding that the most that companies could previously expect for violating a permit was a a weak fine. He expects employees and companies will demand more resources to invest in prevention and safety to avoid facing future criminal charges.

In February, the Commissioners Court approved a 28 percent budget increase for the Pollution Control Department. The investment made little difference during the ITC and KMCO fires. The department was still unprepared for a multi-day response, despite experiencing one during the 2017 Arkema fire. The department told commissioners that it would take days to get air-quality test results related to the ITC fire. Five of the county’s 12 ozone monitors were broken and it had no mobile air-monitoring vehicles at its disposal.

Prosecutors have previously won convictions against ITC for water pollution, but not recently. The company paid a $500 fine for a 1975 conviction and $650 in a 1990 case.

In the decade before the March fire, ITC violated federal and local environmental rules multiple times, racking up fines of more than $65,000 since 2009.

Residents echoed Metzger’s support for more aggressive oversight.

Duncan Stewart lives a few miles from the plant. He wasn’t surprised by the decision to charge ITC. He thinks polluters will take a criminal process more seriously than a simple civil penalty.

“A fine like that is a token for a company” like ITC, Stewart said.