nonflammable

The daylong effort is hazardous because of the high pressure used to test the system with helium, a nonflammable gas.

Discovered in the 1920s by a chemist at General Motors, these compounds were odorless, nonflammable and seemingly nontoxic — all properties that made them useful to industry.

Anhydrous ammonia is a colorless nonflammable liquefied gas.

The fire of that era also destroyed most of the Near North Side of the city, meaning that anything new had to be built in stone or other nonflammable materials.

The report warns that such an event would be difficult for people in the vicinity and first responders to detect, since CO2 is colorless, odorless, and nonflammable.