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plural off-gases also off-gasses
: a gas that is produced as a by-product of an industrial process or that is given off by a manufactured object or material
Refinery off-gases from fluid catalytic cracking could be a source of ethylene.Predicasts Technology Update


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off-gassed; off-gassing

transitive + intransitive

: to give off a typically harmful gas
In addition, OSHA intends to amend the hazard communication provisions of the standard to require hazard warning labels for solid materials capable of off-gassing formaldehyde at levels between 0.1 ppm and 0.5 ppm …Chemical & Engineering News
… there have been environmental concerns about the phenol formaldehyde binders used in most engineered-wood products, which can off-gas.Max Alexander

Word History

First Known Use


1955, in the meaning defined above


1974, in the meaning defined above

Time Traveler
The first known use of off-gas was in 1955

Dictionary Entries Near off-gas

Cite this Entry

“Off-gas.” Dictionary, Merriam-Webster, Accessed 1 Feb. 2023.

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