From the Houston Chronicle: (and thanks to Tom Wald for putting this out this morning on the BIKE email list)
Authorities found the ladder truck driver, Warren Ducote, at fault for the crash that injured 11 people. They say he ran a red light. A police official said on Saturday it was too early to tell whether Ducote would face criminal charges.
Both Houston Fire Department trucks were en route to what firefighters thought was a blaze but turned out to be a Houston public works crew smoke-testing sewer lines.
Ducote ran a red light while headed northbound on Dunlavy and was broad-sided by a pumper truck westbound on Westheimer.