SAN ANTONIO -- Fire tore through a business building Wednesday morning on the city's northeast side, causing an estimated $100,000 in damage.

The two-alarm blaze broke out at around 6:40 a.m. at Christopher Stuart Cast Stone in the 13800 block of Lookout Road near Live Oak.

When firefighters arrived, they found the front of the building fully involved, said District Chief Ron Rodriguez of the San Antonio Fire Department. When flames tore through the roof, a second alarm was sounded and firefighters had to back off.

"That's a signal for us to get out and keep the firefighters safe," Rodriguez said.

The business owner told KSAT 12 News that the office was destroyed but the warehouse appeared to be OK. He also said a partition wall between the office and warehouse kept the fire from spreading.

"It appears that we lost only office equipment and records," Rodriguez said. "It appears that much of their machinery and equipment in the warehouse area was saved."

About 75 firefighters were at the scene and the fire was declared contained around 8 a.m., Rodriguez said.

No injuries were reported.

A cause is under investigation.

The company manufacturers ornamental stone pieces for architectural use.