“Something went wrong,” said the uncle, Albert Ake, 48. “What she told me is that there is nothing dangerous about doing this. That the only thing that could happen is you’re there a little too long and you get frost nip on your fingers.”

The death raised questions about safety in the growing industry of cryotherapy, which is practiced by star athletes and celebrities but is rarely studied and not regulated by any one body. Today, there are cryotherapy centers in New York, Chicago, Los Angeles and elsewhere, though doctors do not agree on its benefits.

In a statement, the owners of the center where Ms. Ake-Salvacion died — a two-store chain called Rejuvenice — said they were “devastated by this accident,” and that they were “voluntarily scrutinizing each and every one of our internal procedures to ensure nothing like this ever happens again.” The company’s website says that its chambers are “equipped with numerous safety features” and that doors are never locked, allowing clients to exit at any time.

On Monday, a week after the accident, it seemed like business as usual at the Henderson store, a narrow storefront on a corner of a busy street of a Las Vegas suburb. There are two forms of cryotherapy offered: a one-person cryochamber, which requires the client to wear earmuffs, a mask, gloves, slippers, socks and underwear; and a three-person cryosauna, which does not require the mask or earmuffs.

Cost is based on treatment and need, and the center offers a deal through Groupon, said Hailey Cap, office manager of Rejuvenice. Ms. Cap, who said she had known Ms. Ake-Salvacion for three years, said that she and other workers at the spa would often use the cryochambers, but never alone.