One or more techniques and/or systems are disclosed for a portable heater that may be used in an area used for human occupancy, to provide heat to that area. Such a heater can be portable, and comprise an environmental detector that senses ambient air conditions, and may provide data used to shut down the heater in threshold conditions. In one implementation, a portable heater for use in high altitudes can comprise a housing configured for portability, in which a combustion region and a fuel supply component are disposed. The heater can comprise an environmental detector with a flameless sensor configured to detect an ambient level of a constituent of the atmosphere, and generate a signal indicative of the constituent level; and a sensor interface that can control flow of fuel from the fuel supply, based at least upon a signal received from the sensor.