Just before noon Tuesday, hundreds of locals and tourists were forced to evacuate the Shops At Rivercenter and Marriott Riverwalk as smoke began to fill the building. The fire department was on scene at the 800 block of Riverwalk by 11:45 a.m. The fire raged for over four hours, drawing 45 response units.

Woody Woodward, a spokesman for the San Antonio Fire Department, told the San Antonio Express News firefighters were focusing on an area of duct work near Tony Roma’s and Luciano. Firefighers believe the fire started as a grease fire and spread to the duct work.

A string of high-profile restaurants in San Antonio have battled fires in the past year. Jacala Mexican Restaurant, Folc, Francis Bogside, King's Bowl, El Tipico and a Grady’s BBQ have all felt the heat. This is the fourth fire-related incident in the past seven years at this location.

The spokesman for the SAFD said the duct work required for sophisticated ventilation systems runs through walls and ceilings, which makes it difficult to access the point of origin. Grease fires must be smothered to extinguish them.

Restaurant fire safety has come a long way in recent years. In 1980, 23,300 restaurants in the U.S. reported a fire. The most recent data for 2014 shows just 8,470 restaurant fires, a 64% decrease.