A Johnston bakery famous for its pizzas and spinach pies was destroyed in an early-morning fire yesterday.

The fire at Palmieri’s Bakery, 624 Killingly St., broke out in a first-floor oven at about 2:30 a.m. and swiftly spread to the second floor, according to the Johnston Fire Department. The fire burned through the natural-gas lines.

Firefighters could not contain the blaze until National Grid workers arrived about 3 a.m. and turned off the gas, said Assistant Chief Thomas Ucci.

Fire crews remained to put out hot spots until 10:30 a.m.

Five or six bakery employees were working when the fire broke out, but no one was injured. One firefighter was taken to Roger Williams Hospital with back pain and released, Ucci said.

“The building was about 100 years old and is a total loss,” Ucci said. The fire marshal’s office is investigating, but Ucci desribed the fire as “not suspicious.”

The bakery, which has been owned by Stephen Palmieri for 36 years, is a popular store, catering business and wholesale bakery, with accounts at supermarkets, clubs and restaurants, said longtime manager Mary Tobin.

Palmieri and Tobin were called to the scene minutes after the fire began and saw the building go up in flames, she said.

“I can’t tell you how many customers came up to us today, with tears in their eyes, to say they’ve been coming here for years,” Tobin said. “It was like a family.”

Tobin said Palmieri said he intended to rebuild on the same location as soon as possible. She said about 20 to 25 people work at the bakery full- or part-time, many of whom have worked there for decades.

“It’s always been a family-run place and it feels that way when you walk in,” Tobin said.

jjordan@projo.com