CNN) -- Firefighters were sifting through rubble in search of survivors of an explosion that they say killed at least three people Thursday near Brazil's largest city.
Civil Defense authorities put the toll at two dead and three missing.
A fireworks factory exploded at 12:30 p.m. (11:30 a.m. ET), leaving dozens injured in a residential area in the industrial hub of Santo Andre, on the outskirts of Sao Paulo.
Some 40 firefighters were on the scene and believed people were under the rubble, Sgt. Cordiero of the Santo Andre fire department told CNN. He declined to give his first name.
The workers were sifting through debris with shovels and at least two pieces of large earth-moving equipment, television pictures from the scene showed.
Sniffer dogs were also on the scene, Cordiero said.
The blast appeared to have destroyed a large section of the building, scattering debris onto surrounding streets. Nearby cars and houses were destroyed, civil defense authorities said in a news release.
Four city blocks have been cordoned off as rescuers conduct their search, they said.
--CNN's Helena DeMoura contributed to this report.
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