A flooded chemical plant in a small town outside Houston is poised to explode as the scope of the devastation caused by Hurricane Harvey came into sharper focus.
The death toll climbed to at least 31, and the fire department in Houston began searching thousands of flooded homes to ensure “no people were left behind”.
Harvey was downgraded to a tropical depression and the floodwaters started dropping across much of the Houston area, but major dangers remained for the US Gulf Coast area.
While conditions in the nation’s fourth-largest city appeared to improve, another crisis related to Harvey emerged at a chemical plant about 25 miles away.
A spokeswoman for the Arkema plant in Crosby, Texas, said the flooded facility had lost power and backup generators, leaving it without refrigeration for chemicals that become volatile as the temperature rises.
“The fire will happen. It will resemble a gasoline fire. It will be explosive and intense in nature,” said Janet Smith, spokeswoman for the French company.
The last of the plant’s employees evacuated on Tuesday and residents within 1.5 miles were told to leave.
Arkema submitted a plan to the government in 2014 outlining a worst-case scenario that said potentially 1.1 million residents could be affected by such an event over a distance of 23 miles, according to information compiled by a non-profit group.
But the company said on Wednesday that a worst-case scenario was “very unlikely”.
The confirmed death toll from Harvey climbed to 31, including six family members – four of them children – whose bodies were pulled on Wednesday from a van that had been swept off a Houston bridge into a bayou.
“Unfortunately, it seems that our worst thoughts are being realised,” Harris County Sheriff Ed Gonzalez said after the van that disappeared over the weekend was found in 10 feet of muddy water.
As the water receded, Houston’s fire department said it would begin a block-by-block search on Thursday of thousands of flooded homes.
Assistant Fire Chief Richard Mann said the searches were to ensure “no people were left behind”.
Forecasters downgraded Harvey to a tropical depression late on Wednesday from a tropical storm but it still has lots of rain and potential damage to spread, with 4ins to 8ins forecast from the Louisiana-Texas line into Tennessee and Kentucky through to Friday.
For much of the Houston area, forecasters said the rain is pretty much over.
“We have good news,” said Jeff Lindner, a meteorologist with the Harris County Flood Control District. “The water levels are going down.”
Houston’s two major airports were up and running again on Wednesday. Officials said they were resuming limited bus and light rail service as well as rubbish collection.
But many thousands of Houston-area homes are under water and could stay that way for days or weeks, and Mr Lindner warned that properties near at least one swollen bayou could still get flooded.
Officials said 911 centres in the Houston area are getting more than 1,000 calls an hour from people seeking help.