In the Houston area, officials said that more than 4,800 people have been rescued by the Coast Guard and local police while countless people are waiting for aid. Residents should ask to see the badges and the credentials of anyone who says they are agents.
"It is not anything toxic", Gonzalez said.
Company officials sought to tamp down the threat, while saying they do expect more fires at the facility owned by the French company Arkema.
At an earlier news conference, Assistant Harris County Fire Chief Bob Royall said the different grades of organic peroxides in a semi-trailer caught fire not long after midnight. Restarting plants under even the best conditions can take a week or more. "Air is not possible".
Crosby resident Lane Averett, 59, told AFP at a church shelter in the town that he was anxious about the animals he had left behind.
"We never expected to lose water", she told the Beaumont Register, adding that patients were being transferred to other regional hospitals via ambulance and helicopter.
"Our whole city is under water right now but we are coming!"
"Had we been a few moments later, they would have been swept underneath (a trestle) and our boats wouldn't have been able to get them", Haley Morrow, spokeswoman for the Beaumont Emergency Management Office, told CNN on Wednesday.
Mayor Derrick Freeman of Port Arthur, a city located about 90 miles east of Houston in Jefferson County, told CBS News that 20,000 homes had as much as 6 feet of water in them.
Meanwhile, Harvey was moving toward southwest Louisiana on Tuesday.
In Crosby, plumes of black smoke filled the morning sky after two explosions at a flooded chemical plant.
Other emissions were released during the planned shutdown of the refinery before the arrival of Harvey, which was then a hurricane but later downgraded to a tropical storm.
"Due to flooding and potential power supply interruption, Valero's Port Arthur refinery has shut down in a safe, controlled manner", the company said in a statement.
More than 30,000 people found refuge in shelters across Texas, from the giant Houston convention center to small churches, according to FEMA.
Houston Mayor Sylvester Turner also implemented a curfew of midnight to 5 a.m.in an apparent response to scattered reports of looting. The storm made landfall again Wednesday morning near the border between Texas and Louisiana after a short time over the Gulf of Mexico. Hundreds of square miles are still underwater, thousands of people remain displaced and new terrors are developing in the wake of the nation's worst hurricane since Katrina in 2005.
Moody's Analytics estimated the economic cost from Harvey for southeast Texas at $US51 billion ($A64 billion) to $US75 billion, ranking it among the costliest storms in U.S. history.