A 10-story commercial building in downtown Portland was evacuated Tuesday after employees inside noticed cracks on the lower half of the structure and feared it would soon collapse.

Portland Fire & Rescue crews responded about 11 a.m. to the Fifth Avenue Building at 1400 S.W. Fifth Ave. after a 911 call. The building houses eBay and OHSU offices as well as a 24-Hour Fitness, a Kindercare Day Care Center, FedEx and other businesses.

Several cracks can be seen on one side of the building from Southwest Fourth Avenue and Clay Street, but the damage appears to be only to the building facade, said Portland Fire & Rescue spokesman Lt. Rich Chatman. There is no danger of the structure collapsing.

No injuries were reported. As of about 1:45 p.m., tenants were allowed to briefly go back inside the building to get their belongings.

Authorities plan to put up scaffolding to shore up a bulge in the structure and prevent more of the facade from falling. The building will cleared for reoccupation some time after that, but it's not yet clear when that would be.

Sidewalks around the building will also be closed until the scaffolding is put up.

Officials do not yet know what caused the damage to the building. Construction is underway on parts of the building, but investigators don't yet know whether the damage is related.

The building was built in 1951 as the main Portland office for the state of Oregon, according to Melvin Mark Companies, which owns the structure. Dan Dittmer, an operations manager with the real estate agency, said he didn't immediately have any information about the building or the damages.

The building owner will be tasked with investigating what caused the damage, City Commissioner Dan Saltzman said. The city will then review the inspection reports, he said.

Portland Fire and Rescue Battalion Chief Andy Ponce did not know of any previous structural issues with the building, he told reporters Tuesday afternoon. The fire department has not responded to any calls at the building in the past, to his knowledge.

Gloria Richard, an OHSU employee on the second floor, said she knew she wasn't experiencing a building fire drill when lights began to flicker and the fire alarm went off without advance notice.

"I was like, 'What is going on?'" she said. "All I could see was people running."

OHSU employee Brandilee Schwark said she was on the eighth floor when she also heard fire alarms going off. Once outside, she saw the building was bowed on one side.

Children and staff at KinderCare have been moved across the street to the lobby of Hotel Modera, according to the day-care center.

The 200 eBay employees who work on five floors in the Fifth Avenue Building have been told to go home for the day, said Ryan Moore, a company spokesman. Details on an alternative work site are still being discussed while the downtown Portland offices are closed.

The building closure could cause delays in some requests for medical records, said OHSU spokeswoman Tracy Brawley, but shouldn't heavily impact patients. The hospital has more than 100 non-clinical employees who occupy four building floors.

Portland police temporarily blocked a two-block radius around the building, but have since reopened the area to traffic. Delays in MAX service to downtown Portland stations on Fifth and Sixth avenues should be expected until around 2:30 p.m., TriMet said.

Collapse threat forces evacuation of downtown Portland building Collapse threat forces evacuation of downtown Portland building at SW 4th Ave. and Clay. Posted by The Oregonian on Tuesday, April 11, 2017

-- Samantha Matsumoto

503-294-4001; @SMatsumoto55

Everton Bailey Jr., Molly Harbarger, Stephanie Yao Long and Mike Rogoway of The Oregonian/OregonLive staff contributed to this report.

