Houston short on inspectors to test its air and water after Harvey.

Houston needs help monitoring the threat of toxic pollution to the city’s water, soil and air from Tropical Storm Harvey’s destructive flooding, a city health department official said.

The Houston Health Department has two employees to routinely test the city’s waterways, but that isn’t enough to quickly monitor the storm’s effects across Houston’s vast network of bayous, said

Loren Raun,

chief environmental science officer for the health department in an interview Saturday.

“It’s too big of a problem,” Ms. Raun said. “We really need to be sampling everywhere.”

Houston is a major hub for petroleum and chemical manufacturing and is home to eight Superfund sites, according to the U.S. Environmental Protection Agency. Ms. Raun said she reached out to the EPA on Friday, asking for help testing the city’s Superfund sites and as of Sunday morning she was still waiting for a response from the agency’s Regional Emergency Operations Center. The EPA didn’t immediately respond to requests for comment.

Without additional federal or state help, local inspectors will do targeted air testing, but their ability to test water is limited, said 

Donald Richner,

senior project manager for the bureau of pollution control and prevention within the health department’s environmental division. “We would appreciate any assistance,” he said.

City inspectors will drive around the perimeter of the industrial locations with air monitors and infrared cameras, looking for evidence of leaking hazardous waste. They will then test water where there are signs of contaminated air, Ms. Raun said.

The EPA said in a press release Sunday that it continues to work with Texas and local authorizes to assess Harvey’s impact on drinking water, wastewater plans and the environment. The agency added that it would target industrial and hazardous-waste sites for floodwater sampling. Cleanup crews at Superfund sites continue to provide updates to EPA and Texas environmental officials, the agency said.

Aerial images and contact with cleanup officials at 41 southeast Texas Superfund sites as of Saturday afternoon showed 28 escaped damage or excessive flooding. Two more locations swamped by the storm’s record rains don’t need emergency cleanup, the EPA said.

The remaining 11 sites remained too flooded to inspect, the EPA said Sunday, including the San Jacinto Waste Pits, where toxic paper-mill waste is covered by an armored cap. The cap “has required many repairs and extensive maintenance,” the EPA said in September.

The San Jacinto Waste Pits fall outside Houston’s city limits but are a concern, Ms. Raun said. “Once the cap is underwater, we’re worried about the integrity of it,” she said.

The EPA said an inspection of the San Jacinto Waste Pits by boat was scheduled Monday. Divers would examine the cap “when conditions allow,” the EPA said.

Houston’s Geneva Industries/Fuhrmann Energy petrochemical Superfund site was also too flooded to inspect, the EPA said.

One of Ms. Raun’s chief concerns is the threat of toxic pollutants from Houston’s runoff reaching downstream industries and ecosystems, contaminating the soil and entering the air through evaporation.

The city’s main waterway, the Buffalo Bayou, channels runoff from the surrounding 102 square miles into the Houston Shipping Channel. Those waters eventually make their way to the Gulf of Mexico, she said.

That is why Ms. Raun emailed EPA officials Friday to request help taking and testing water samples near Superfund locations. An EPA official replied Friday to say he had forwarded her request to the agency’s Regional Emergency Operations Center.

In the meantime, Houston Health Department air-inspection teams will begin to fan out Tuesday to monitor air quality around the city’s petroleum and chemical manufacturers, targeting roughly 100 of the largest locations first, Mr. Richner said.

“We’ll start with them because when they have a problem, it’s usually bigger than anyone else’s,” Mr. Richner said.

They will also contact companies for reports of damage and to offer assistance to find potential leaks.

But checking up on smaller companies, including those that store or mix toxic chemicals and waste, will take time, he said. “It’s a big city and we’re a small bureau.”

The city employs six air-pollution inspectors and another half-dozen engineers and chemists who monitor air quality. Inspectors have responded to two company reports of hazardous leaks since Thursday, though it isn’t clear is the leaks are storm-related, Mr. Richner said.

A joint Texas and Houston network of environmental monitoring stations isn’t yet fully operating after officials shut it down ahead of the storm to prevent damage, he said. Typically, the network flags potential trouble spots, he said. “Without the network we are sort of blind,” he said.

The EPA said Sunday that 70% of air-monitoring equipment that had been shut down ahead of the storm in the Houston area, Corpus Christi and Beaumont is back up and running. The remaining equipment should be operating by next week. “Monitors are showing that air quality at this time is not concerning and local residents should not be concerned about air-quality issues related to the effects of the storm,” the EPA said.

Corrections & Amplifications
An EPA official replied to Ms. Raun’s request for federal help taking and testing water samples near Superfund locations. An earlier version of this article incorrectly stated that a Food and Drug Administration official replied to her request. Also, the EPA said the 11 remaining Superfund sites in southeast Texas were too flooded to inspect. An earlier version of this article incorrectly stated 13 sites were too flooded. (Sept. 3, 2017)

Write to Melanie Evans at Melanie.Evans@wsj.com