CHESTER, Pa. (CBS) -- Nineteen people were displaced overnight after fire tore through several rowhomes in Chester, Delaware County.

Flames broke out around 1:30 a.m. Monday along the 400 block of Bickley Place.

Authorities say the fire started in a vacant home and quickly spread to three occupied houses.

All four homes, including the vacant house, were seriously damaged by the fire. A fifth home was damaged by smoke.

The fire was placed under control in about an hour-and-a-half.

No one was injured, but the American Red Cross was helping five displaced families of eight adults and 11 children.

Fire officials had already been investigating a separate vacant house blaze on the block a few days ago.

The cause of this fire has not been determined.