PHILADELPHIA (CBS) — An investigation into Friday’s refinery explosion in South Philadelphia continues as investigators try to determine a cause. Officials said they are currently putting together a group to address the public’s concerns, however, a cause into what caused the blast could take “months or years.”

The fire at the Philadelphia Energy Solutions refinery raged for more than 24 hours and was finally extinguished Saturday afternoon. PES says the fire started in a unit used to create a component for high octane gas.

Multiple tests conducted by the city’s Department of Public Health over the past several days have determined the air quality to be normal and pose no threat to the public. Five people suffered minor injuries, but are going to be OK.

Philadelphia Managing Director Brian Abernathy announced Tuesday during a press conference the city is currently putting together a group consisting of PES officials, city officials, environmental experts and scientists, emergency management and community members.

Abernathy says the group will aim at answering the public’s recent concerns following the blast: Is the refinery safe? Is it safe for workers and is it safe for the surrounding community? Does PES have appropriate measures in place to prevent a catastrophic failure? Was our response and was the response of PES adequate and appropriate? What are the environmental and public safety risks around the refinery? Should the refinery close?

“The administration believes that Philadelphia Energy Solutions is a vital part of our community but we also recognize the real concerns this incident raised for your neighbors and for the city as a whole,” Abernathy said. “The investigation into this accident will take months, if not, years to complete. We can’t wait that long to provide an answer to our residents, and I am optimistic that this working group can go a long way to providing those answers into the future.”

Officials plan to hold an organized meeting on July 1 and a public meeting by the end of the July.

Members of the public with questions can call the PES Community Information Hotline at ‪‪215-339-7300.