By Gina Yarbrough

La Mesa, CA–About 30 people were displaced after a structure fire broke out Monday night at an apartment complex in East County, fire officials said.

Heartland Fire and Rescue, San Diego Fire Department, San Miguel Fire and Rescue, American Medical Response, and La Mesa Police Department responded to the blaze just after 7:30 p.m. at the Spring Hill Apartments at 4341 Spring Street in La Mesa.

A total of 18 fire crews and 33 fire personnel knocked down the fire around 8:05 p.m. The sprinkler system inside the apartment building did activate, which helped prevent the fire from spreading to other units. Only one unit was directly affected by the fire, but water from the sprinkler system affected an additional fifteen units, fire officials stated in a release. 

The American Red Cross was called to assist the displaced residents.

No injuries to civilians or firefighters were reported.

The exact cause of the fire has yet to be determined.