Juan López had just returned home from his job supervising the cleaning of giant tanks that hold toxic chemicals produced along the Houston Ship Channel, one of the largest petrochemical complexes in the world.He was ready to sit down to dinner with his wife, Pamela López, and their four school-age children at their small house across the highway from the plants.But as the family gathered, the facilities were still burning off chemical emissions, sending clouds of leftover toxics toward their two-bedroom home, hitting them on some days with distinct and worrisome smells — and leaving Mr. López concerned about the health of their children.“I make good money where I’m at,” he said. “But I always felt like it was only me that was getting exposed, because I am working in the tanks with the chemicals. When the smell comes, all we can really do is try to keep everyone inside. Is that enough? I just don’t know.”He has reason to worry. Two recent assessments, by the Environmental Protection Agency and city officials in Houston, found that residents were at higher risk of developing leukemia and other cancers than people who lived farther from the chemical plants.These same worries afflict households in Illinois, Louisiana, West Virginia and other spots around the United States where families live near manufacturing facilities that make or use these cancer-causing chemicals.“Sacrifice zones — that’s what we call them,” said Ana Parras, a founder of Texas Environmental Justice Advocacy Services, which sued the E.P.A. starting in 2020 to push for tighter rules on toxics. “These areas here are paying the price for the rest of the nation, really.”The chemical plants were still burning off emissions as the López family ate dinner.Meridith Kohut for The New York TimesPamela López, 32, comforting her 9-year-old daughter, Mahliyah Angelie, who had a headache.Meridith Kohut for The New York TimesWaves of toxic chemicals drift toward the López family home at unpredictable moments, day and night.Meridith Kohut for The New York TimesAfter years of only intermittent action by the federal government and opposition from the industry, the Biden administration is racing to impose restrictions on certain toxic air releases of the sort that plague Deer Park, while also moving to ban or restrict some of the most hazardous chemicals entirely.The proposed measures would significantly cut releases of a number of cancer-causing chemicals from plants in Texas, including four of those across the highway from the López family.Companies from a variety of industries, including those that produce the substances and those that use them, are pressuring the administration to water down some of the rules, saying the repercussions of a ban or new restrictions could be economically crippling.Few communities are at greater risk than Deer Park, and few people experience the trade-offs between economic considerations and health more than Mr. López, for whom the petrochemical industry is both the source of his family income and a threat to their health.Mr. López, 33, did not graduate from high school and is proud of how much he is paid to supervise the cleaning of the chemical tanks, which his crew climbs into and scrubs from the inside, an extremely dangerous job.But he suggested that the job did not blind him to the risks the plants pose to his family, saying that “just because you help me make a paycheck does not mean you are doing everything right.”Waves of toxic chemicals drift toward the family home at unpredictable moments, day and night. Mr. López wears protective gear at work. But there are no such measures at the house, where the children ride bikes in the driveway and play with a puppy named Dharma. From the swing set in their backyard, they can see the flares from the nearby plants.