Gregg said eight men and one woman were treated.
A man who lives nearby told KOMO-TV that the blast shook him out of bed.
“Thought it was an earthquake; way too loud to be a gunshot. So I got out of bed, checked on the family, and my family’s good. So I went outside and saw smoke,” Josh Coolbaugh said.
Crews worked to shut off natural gas in neighborhood. Puget Sound Energy spokeswoman Christina Donegan said a survey team will then move in.
Donegan said their focus will be to determine if there was an issue with gas to the building or something inside the building.