A major grass fire burned upward of 400 acres, shut down a highway and caused several homes to be evacuated before firefighters contained it Sunday night north of Edinburg, authorities said.

No one was injured and no structure was damaged, although houses along Chapa Road were evacuated over fear of thick smoke, and fire breaks were plowed to protect homes, saidDomingo Hinojosa, Linn-San Manuel fire chief.

In total, eight structures were threatened by the fire. One was home to a 90-year-old man who had to be removed quickly as flames advanced toward the house, Hinojosa said.

“”That was the first thing we did was evacuate him,”” he said.

Though Edinburg and Linn-San Manuel firefighters shouldered the effort for a while, eventually 100 firefighters responded from a dozen departments including Pharr, McAllen,Mission, San Juan, Alamo and Alton. The blaze led authorities to close Highway 186 east of Expressway 281.

At about 7:45 p.m., the fire was contained with only hot spots left to extinguish, Hinojosa said. The cause of the fire, which broke out about 5:56 p.m. on the side of the road, is under investigation.

During the blaze, authorities were concerned about the strong wind. They said that grass and brush is especially dry from the recent freeze, and they warned people not to throw out cigarette butts or do any burning.

“”Literally, any little spark will start something this big,”” Hinojosa said.