Two people were taken to local hospitals for treatment after the blast, which happened around 8:05 p.m. on Hale Street and Butler Avenue, borough officials confirmed.
In a 12 p.m. update, borough manager Justin Keller updated the number of deaths to five and said, "all were accounted for."
Pottstown school officials canceled classes Friday.
Photos posted to Twitter by Pottstown Mercury reporter Evan Brandt show debris from the scene.
Any affected resident who needs assistance from the Red Cross was asked to go to Pottstown Senior High School at 750 N. Washington Street in Pottstown.
The cause of the explosion remains under investigation.
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