WEST, Texas—This small town just off I-35, known in central Texas as a good place to pull off the highway for Czech pastries, spent Thursday coming to grips with a landscape of flattened homes and diminishing hopes that friends and neighbors will be found alive in the aftermath of a devastating explosion.

The blast Wednesday night at a fertilizer plant here has left more than a dozen dead, and 150 injured. It destroyed a school and 75 or so homes—damaging a sizable portion of a tightknit town of 2,800 with a Czech heritage...