Molds also emit volatile chemicals that some experts believe could affect the human nervous system. Among them is Joan Bennett, a distinguished professor of plant biology and pathology at Rutgers University, who has devoted her career to the study of fungal toxins. She was living in New Orleans during the storm, and she recalls that while some health experts were worried about heavy-metal poisoning or cholera, she was worried about fungus.

“I’m still surprised it didn’t receive more attention from the scientific community, she said in a recent interview. “The city was rife with mold; everything organic decayed. A few people did some very superficial spore counts and they were off the scale, but at the time almost no one studied it because the focus was elsewhere. So I did my own study.”

The smell of the fungi in her house got so strong after the flooding that it gave her headaches and made her nauseated. As she evacuated, wearing a mask and gloves, she took samples of the mold along with her valued possessions. Her lab at Rutgers went on to report that the volatile organic compounds emitted by the mold, known as mushroom alcohol, had some bizarre effects on fruit flies. For one, they affected genes involved in handling and transporting dopamine in a way that mimicked the pathology of Parkinson’s disease in humans.

“More biologists ought to be looking at gas-phase compounds, because I’m quite certain we’ll find a lot of unexpected effects that we’ve been ignoring,” said Bennett.

This is where Trump’s words in support of Houston ring hollow.

Under his administration, the funding of science to better understand the health consequences of mold exposure stands to be slashed. Meanwhile, the significance of mold in human lives is expected to increase with rising sea levels and catastrophic weather events. The perennial intensification of severe weather patterns over the Gulf Coast has made flooding increasingly common, at least partly due to the warming of the ocean.

The Environmental Protection Agency, which would typically be tasked with mitigating the health effects of mold in Houston, is currently uprooting the regulations intended to reduce carbon emissions that raise the likelihood of severe weather events. The agency stands only less equipped now to deal with environmental mold contamination than it did in New Orleans.

In Houston, short-term rescue funding is essential to saving lives, and supporting it is politically necessary. But most of the looming threats to human wellbeing will outlast the immediate displays of concern. They will play out when the water and the cameras are gone, and when emergency funds allocated to Houston are exhausted. Mold will mark the divide between people who can afford to escape it and people for whom the storm doesn’t end.