Police in Massachusetts are investigating after someone broke into a storage room at a Longmeadow park and poured muriatic acid — a harsh chemical used for cleaning or maintaining a pool’s pH balance — onto three of the park’s slides.

Police and firefighters were called to Bliss Park Sunday morning when visitors reported a suspicious substance on the playground equipment, according to the Longmeadow Fire Department.

A second call at about the same time brought firefighters and emergency medical services to a nearby home, where two children had “burn like injuries” after leaving the park.

Investigators determined that the perpetrator or perpetrators broke into the pump room in the basement of the pool building after climbing over two fences and tearing off the cover to a ventilation shaft. They used the ventilation shaft to enter the building.

The Massachusetts State Police crime lab took several items of evidence back to their lab for analysis and fingerprinting.

No charges have been filed in the incident. The fire department said that the chemicals had been secured properly and that the suspects required “a great deal of effort” to get to the chemicals.

“We suspect that the perpetrators may have suffered acid burns to their hands or arms and their clothing may have indications of being degraded from contact with the acid,” the fire department said.

“If you know of someone with new burns to their hands or arms or may have had burned clothing, please also notify Longmeadow police.” they said.

The city of Longmeadow brought in a specialty contractor to clean up the area, which will remain closed “until we determine the next step.

The rest of the park is open, the fire department said.

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[Featured image: Bliss Park playground. The swimming area is behind the playground/Google Maps]