Three firefighters and seven police officers are being treated for various minor injuries after battling a large 3-alarm fire at a pool supply warehouse in Frisco on Wednesday morning.

According to the City of Frisco, fire department dispatch received a call from a warehouse employee at approximately 7:45 a.m. about a structure fire at a swimming pool supply business.

According to Kelly Kistner, the Frisco Fire Department’s fire marshal and public information officer, preliminary information indicates the fire likely started from a chemical reaction on a pallet of materials outside the building and then spread to a truck and then to the warehouse.

“A company employee noticed a vapor,” Kistner said. “A fire and explosion followed. A nearby truck and the company’s building caught fire. But it’s important to note, damage to the interior is limited thanks to the building’s sprinkler system.”

The fire sent a large plume of flames and smoke into the air that could be seen from several miles away. Because it involved burning chemicals, a shelter-in-place order was issued. By 9:30 a.m., the fire department said the fire had been tapped out and the shelter order was lifted.

Kelly Kistner with the Frisco Fire Department says 10 first responders were hospitalized after being exposed to burning chemicals in a large warehouse fire on Wednesday. 

Kistner said Wednesday afternoon that 10 first responders, including three firefighters and seven police officers, suffered a range of symptoms “that they didn’t come to work with” after being exposed to the burning chemicals and that out of an abundance of caution, they transported them to hospitals to be evaluated.

“All of those are due to exposure from air inhalation. They are all at local hospitals. They are all stable and are under observation at this point,” Kistner said.

Kistner said he didn’t know who was suffering from what condition but that common symptoms due to exposure might include itchy eyes, skin irritation, inhalation issues, or difficulty breathing.

At 1:30 p.m., all 10 first responders were still at the hospital under observation.

Dr. Benjamin Brown, an ER physician at Medical City Plano, treated some of the first responders.

“We’re a level one trauma and burn center so we see it all so you never know what you’re going to get and today was a unique circumstance with our first responders,” said Dr. Brown.

He says symptoms from chemical exposure can range from irritated eyes and skin to trouble breathing.

“I think the concern was that if there is a significant burn injury that one of our first responders develops because it can be a delayed reaction, you want them to be at a center that’s capable of handling that situation,” said Dr. Brown.

He says all ten first responders are recovering and expected to be OK.

No other injuries have been reported. Kistner said that anyone in the vicinity of the fire and was having trouble breathing or showing other symptoms should seek medical care.

According to Frisco officials, the three primary chemicals involved in the fire were pool salt, trichlor (also known as chlorine tablets), and hypochlorite (also known as pool shock). Kistner said that two of those chemicals are considered hazardous materials.

Kistner said the Texas Commission on Environmental Quality was measuring the air quality at the scene and that the air quality was good.

“We are getting no readings in the air. The air quality is clear and it is safe,” Kistner said Wednesday afternoon.

HAZMAT crews were called to the fire to help contain the chemicals released during the fire. The Frisco Fire Department is also working with the Frisco Public Works Department to help manage the stormwater and potential runoff caused by the chemicals released during the fire.

Kistner said firefighters upgraded the fire to a second alarm while heading to the scene and called for a third alarm after arriving at the warehouse. Adding alarms increases the firefighters’ response, adding trucks, engines, and personnel available to respond to an emergency.

Kistner said in all 78 people responded to the fire including 58 firefighters, 12 police officers and eight public works employees.

As firefighters worked to extinguish the fire, FC Dallas postponed all scheduled workouts until the Frisco Fire Department gave the all-clear. Meanwhile, a Frisco ISD spokesperson said district operations will proceed normally.

“The Frisco Fire Department has lifted the shelter in place, and Frisco ISD has continued operations as normal. Learn more about Frisco ISD’s emergency response here,” a school district spokesperson said. 

Both the Frisco and Little Elm fire departments responded to the fire. The Colony Fire Department also helped to backfill Frisco fire stations during the blaze, Kistner said.

According to the Frisco Fire Department, the investigation into this fire is ongoing.

NBC 5 requested a response from Texas Pool Supply but has not received one yet.