The Veteran’s Health Administration (VA) now requires that all veterans’ home oxygen installations (both stationary and portable) must be fitted with thermal fuses (firebreaks). More information
Elsewhere, while as yet there is no law that specifically says firebreaks have to be fitted in the US, to legally market an oxygen concentrator it must have gone through the 510(k) process to demonstrate that the device is substantially equivalent to one legally in commercial distribution in the United States. If the ISO standard (ISO 80601-2-69:2014) was used to demonstrate the safety of the device, a firebreak is a requirement.