JACKSONVILLE, N.C. (WITN) – The city of Jacksonville has released what chemicals were accidentally mixed together that sparked yesterday’s evacuation of an apartment complex.

Jacksonville Public Safety says a private transport contractor mistakenly put zinc orthophosphate into a storage tank containing sulfuric acid at the city’s water treatment plant.

The accident happened around 11 a.m. Tuesday to the plant on New Frontier Way for a hazmat situation.

Crews found that the two chemicals used in the water treatment process had been unintentionally mixed by a private transport contractor. We’re told both chemicals were contained in a storage tank.

The city says they decided, out of an abundance of caution, to evacuate the immediate areas, which included residents living at Arlington West apartments.

We’re told an isolation area was created and monitored by teams throughout the night.

In a press release, the city says that there are “no health hazards to the general public” and that the city’s water system has not been impacted.

Sulfuric acid, the city says, is used to lower pH levels of incoming water and is removed in the treatment process before the water goes out to homes.

Zinc orthophosphate is a corrosion inhibitor that helps ensure the integrity of pipes and valves.

The city says an environmental remediation company is at the plant “to ensure proper cleanup and identify the need for any additional actions.”

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Jacksonville’s public safety director tells WITN that their agency is working to confirm the chemicals involved in a water treatment plant spill that temporarily forced residents from an apartment complex.

WITN has asked the city’s public safety department why it would not share what the chemical was that was spilled.

Director of Public Safety Michael Yaniero responded to an email Tuesday evening saying that this is an evolving incident, “and until we have an opportunity to confirm the chemicals by inspecting the area where the incident occurred it would be premature to release the information at this time. “

Yaniero says once they confirm the chemicals involved the would respond to our request.

Yaniero says fire personnel are still at the scene and the chemical release is contained.

That evacuation order was lifted just before 5:00 p.m. for those living at Arlington West apartments on New Frontier Way.

The city originally didn’t say the spill happened at its treatment plant. Only when directly asked by WITN did a city spokeswoman confirm the spill occurred at their own facility.

Residents of the complex were also in the dark about was going on. “What was the reason for us to evacuate in the first place? I mean, tell me why I had to leave and I really would appreciate that,” said Adrian Paat, Arlington West resident. “And now, should I feel insecure, I mean thank God I got an air purifier in my apartment. But, you know, I got COPD and emphysema, so will that affect my health as well?”

In a news release late this afternoon, the city said it happened at a chemical storage tank and that the evacuation was done “in an abundance of caution as the chemicals naturally dissipate.”

Shortly before 5:00 p.m. a police officer told them it was now safe to return to their homes, and that authorities would continue to monitor air in the area.

The city says while they do not anticipate any changes, residents should be prepared “on the chance there may be a secondary evacuation.”