A four-alarm fire destroyed four businesses housed in a building in the Bywater neighborhood Saturday afternoon, according to the New Orleans Fire Department.

The department received a call about the blaze at 1:35 p.m.

The first firefighters arrived at 3620 Royal St. five minutes later and found a large two-story metal warehouse fully engulfed in flames. A second alarm was then struck.

Firefighters initially attacked the fire from the interior but had to pull out as the roof began to collapse, according to a department news release.

Stored chemicals and paints and the intense heat caused firefighters to strike third and fourth alarms to summon more assistance.

In all, 72 firefighters in 28 units were called to the scene.

The building was home to four businesses: New Orleans Art Supply, BARK Pet Supplies, the Frame Gallery and the New Orleans Conservation Guild.

One of the business owners went up to investigate flames coming from a vent in the rear second story of the building and called the Fire Department.

The fire was brought under control by 4:15 p.m.

There were no injuries, and the cause is under investigation.