BEAUMONT, Texas — President Donald Trump arrived Saturday to visit areas devastated by Hurricane Harvey as people here continue to clean up and assess the damage.

Texas officials warned some of the floodwaters won’t recede for days and some, such as areas along the Brazos River, not until after next week.

The misery endured in the state’s southeast corner, where a crippled municipal water system left residents lacking running water, unable to flush toilets, desperate for basic sanitation and fearful for their health.

On Friday a massive fire sent up a towering pillar of acrid, black smoke from the Arkema chemical plant northeast of Houston hours after company officials said they could do nothing to stop 19.5 tons of volatile chemicals from igniting.

Beaumont’s dire situation and the uncontrolled chemical fire near Crosby provided vivid reminders of the cascading effects of a natural disaster: wind, storm surge, torrential rain, floodwaters and now all the secondary consequences, including industrial accidents, environmental contamination, and broad concerns about sickness and disease.

Trump’s Office of Management and Budget on Friday night sent a request to House Speaker Paul Ryan, R-Wisconsin, for $7.85 billion for response and recovery to the hurricane, describing the money as a “down payment” on the president’s promise to help states recover from the storm.

More than 30,000 federal workers have been deployed.

In Crosby, residents remained evacuated Friday within a 1.5-mile radius of the burning Arkema chemical plant. The plant lost power and its backup generators were flooded earlier this week, leaving workers unable to continue refrigerating volatile organic peroxides. The chemicals combust if not kept cool.

As an emergency measure, the chemicals were moved into nine box trailers, one of which burned Thursday. The floodwaters have now receded, but Daryl Roberts, Arkema’s vice president of manufacturing, said Friday that the company can’t restart refrigeration because the electrical infrastructure has been underwater for a week.

Friday afternoon, chemicals in another of the trailers caught fire. The heat from the blaze then ignited the chemicals in an adjacent trailer. The two trailers burned simultaneously, producing multiple explosions and fireballs, said Robert Royall Jr., assistant chief of emergency operations for the Harris County Fire Marshal’s Office. That left six intact trailers, parked in a remote section of the plant, each holding chemicals steadily warming and likely to ignite. “We could see all six of these containers engage really quickly,” Arkema executive Richard Rennard said Friday evening.

In Beaumont, conditions in two large shelters holding 1,400 storm survivors became so risky Friday that officials were forced to evacuate as many people as possible. The officials said they couldn’t take care of people without access to water.

Many of Beaumont’s 118,000 residents tried to leave this week but were blocked by high water when Harvey, still a tropical storm and making a second landfall, turned the city into an island. They had no choice but to turn back, often choosing to drive the wrongd way on flooded Highway 90.

Government resources for Beaumont appeared slow to arrive Friday, and tempers flared as people scoured grocery stores for whatever food was left.

“When you take water out of the picture, people start to panic a bit,” said Haley Morrow, a police spokeswoman.

At the George R. Brown Convention Center in Houston, where 7,500 people have taken refuge, the U.S. Department of Health and Human Services reported treating 420 people, some complaining of diarrhea or vomiting that could be associated with a virus or contaminated floodwater.

The convention center has seen a number of drug overdoses, and people have arrived seeking methadone or other opioid-addiction treatments and have been told none are available. CVS and Walgreens have set up mobile pharmacies there with limited stocks of medication.

Statewide, more than 42,000 people have taken refuge in shelters, according to FEMA. Myriad more are dislocated, staying with friends, family or strangers. On Friday, Houston Mayor Sylvester Turner called for residents near the Addicks and Barker reservoirs to evacuate as the Army Corps of Engineers continues to release water from them.

Texas is switching from search-and-rescue mode to recovery mode. As of midday Friday, officials across Texas had recorded at least 45 deaths confirmed or suspected to be related to the storm.

The scarcity of gasoline has become a preoccupation, too, as motorists in many cities — even far from the major flood zone — have found stations sucked dry. Texas Gov. Greg Abbott, R, blamed media reports about gas shortages and an ensuing rush on the filling stations.

“There’s plenty of gasoline in the state of Texas,” Abbott said. “Don’t worry; we will not run out, and we will be back to our normal pattern before you know it.”

The weather has cooperated late this week, with bright sunshine replacing days of downpour. A ridge of high pressure in the atmosphere should keep any developing tropical system in the Gulf of Mexico far away from Texas – an improved outlook since Thursday.

Most who lost power in the storm now have it back. But American Electric Power, a Texas utility, estimated that the cities of Rockport, Fulton and Aransas Pass would not have power fully restored until Sept. 8 — two weeks after Harvey first made landfall.

At least 197,000 homes have been damaged, the Texas Department of Public Safety reported Saturday, more than 12,600 of them destroyed. But those numbers are certain to rise, as the estimates are preliminary and often do not include damage to areas officials haven’t yet been able to access due to the floods.

More than 457,000 people have registered so far for FEMA disaster assistance, according to the agency.

In Port Arthur, a city about 105 miles east of Houston that is ringed by refineries, the floodwater that rose so dramatically earlier in the week, requiring frantic evacuations, was taking its time to recede Friday. Some neighborhoods still had waist-deep water. Convenience stores and gas stations had started to reopen, and signs of normalcy began to appear.

In the El Vista neighborhood, Paul Jackson said the water had dropped about a foot, although it was still up to his thighs.

“That’s promising for us,” said Jackson, 50, who has been living in a camper parked along the highway at the entrance to his neighborhood.

Some residents had begun getting texts from FEMA alerting them that they were eligible for hotel room vouchers.

In Beaumont, about 95 miles east of Houston, some managed to fly out of town after an initial attempt to leave by bus was stymied by high water. Others left shelters and returned home. A line of hundreds of cars snaked along a highway frontage road as motorists queued up for water being handed out by the city and donated by the Texas grocery chain H-E-B.

Beaumont took on a ghostly quality. Grocery stores and restaurants appeared open at first glance and in the evening were illuminated and seemed inviting. Motorists circled them, but there was no going inside. Store aisles were empty, the doors locked and protected by sandbags.

With no running water, there was little cooking that could be done and no way for employees to wash their hands. No fresh produce or supplies could be delivered to Beaumont through the floodwaters encircling the city.

The odor of flood rot began to permeate the air.

Pamela Starks, 59, pushed her cart inside the Walmart Superstore, getting lucky enough to nab four cases of water.

“They got water?” another female shopper asked anxiously.

“It’s gone,” Starks replied.

Outside, Angela Williams, 48, stood with her sister, son, daughter-in-law and two toddler grandchildren in the sun. The family had been rescued three days earlier from their flooded homes in Port Arthur.

Their first shelter flooded. They moved to a second shelter, but there was no food and no water. Now they were crowded — 13 people all told — into the small home of a friend who also had no running water.

It was midafternoon, and they had just had their first meal of the day: one doughnut for each person.