Fire retardant, the reddish liquid dropped from planes to slow spreading flames, has become an indispensable tool for saving lives and property from more frequent and intense wildfires. But the entire supply of the product in the United States is controlled by a single company.

That company, Perimeter Solutions, has deployed an extensive lobbying and public-relations campaign to undercut would-be rivals, even as government officials have voiced concerns about the risks of relying on one source for such an essential product, a New York Times investigation found.

Perimeter has used its dominance to boost profits at the expense of federal and state government agencies — its biggest customers.

The retardant that California’s firefighting agency dropped to protect Los Angeles in January cost 20 to 30 percent more than it did four years ago, substantially outpacing inflation, according to state contracts obtained through a public records request. The U.S. government’s spending on the substance roughly doubled to more than $250 million over the same period, federal data shows.

The rising prices have helped fuel a windfall for Perimeter and the investors who orchestrated a deal to buy the company in 2021 and take it public. Since then, Perimeter’s profits have roughly doubled, and the five architects of the acquisition have together reaped roughly $200 million in cash and stock, according to regulatory filings. The rising profits are not just because of increased demand. The company is keeping more of every dollar in sales thanks to its strategy of cutting costs and hiking prices, executives have said.