Three Hawaiian Electric Co. employees suffered first- and second-degree burns while working on an underground power line near Pensacola Street this morning.

Honolulu Emergency Medical Services said paramedics responded to an 8:30 a.m. call at Pensacola and Kamaile Streets.

EMS said personnel treated three men, ages 34, 36 and 56, who were in serious condition. Their identities were not released.

A Hawaiian Electric spokesperson said three employees were working on an underground power line near the intersection at about 8:30 a.m. when there was an arc flash, which happens when electricity jumps from one conductor to another.

Hawaiian Electric initially said two workers suffered electrical burns and were taken to a hospital with non-life-threatening injuries, and that the third worker was treated at the scene, but did not require hospitalization. Later, the company said all three were taken to Straub Medical Center for evaluation and have since been released.

The cause of the arc flash is under investigation, Hawaiian Electric said.

Hawaiian Electric said 60 customers were briefly without power in the area after the incident but that service has been restored.