Which gas is produced when heat and ultraviolet radiation from the arc decompose vapors from chlorinated hydrocarbons found in cleaners, degreasers, and solvents?

Which gas is produced when heat and ultraviolet radiation from the arc decompose vapors from chlorinated hydrocarbons found in cleaners, degreasers, and solvents?

• A. Carbon Monoxide
• B. Phosgene Gas
• C. Ozone
• D. Nitrogen Oxides

Answer: (B)

When chlorinated hydrocarbon vapors are exposed to the intense heat and ultraviolet radiation of a welding arc, the molecules break apart and can recombine to form phosgene gas (carbonyl chloride). This is a particularly dangerous hazard because phosgene is highly toxic and can cause severe lung damage even at low concentrations. The arc provides both heat and UV energy that facilitate the breakdown of chlorine-containing solvents such as methylene chloride, carbon tetrachloride, or perchloroethylene, leading to phosgene formation. Other gases mentioned are associated with different processes: carbon monoxide comes from incomplete combustion of carbon-based fuels, ozone forms when UV light reacts with oxygen in the air, and nitrogen oxides arise from very high-temperature reactions between nitrogen and oxygen in the flame. In the specific scenario of heated chlorinated hydrocarbon vapors near an arc, phosgene is the gas produced.

When chlorinated hydrocarbon vapors are exposed to the intense heat and ultraviolet radiation of a welding arc, the molecules break apart and can recombine to form phosgene gas (carbonyl chloride). This is a particularly dangerous hazard because phosgene is highly toxic and can cause severe lung damage even at low concentrations. The arc provides both heat and UV energy that facilitate the breakdown of chlorine-containing solvents such as methylene chloride, carbon tetrachloride, or perchloroethylene, leading to phosgene formation.

Other gases mentioned are associated with different processes: carbon monoxide comes from incomplete combustion of carbon-based fuels, ozone forms when UV light reacts with oxygen in the air, and nitrogen oxides arise from very high-temperature reactions between nitrogen and oxygen in the flame. In the specific scenario of heated chlorinated hydrocarbon vapors near an arc, phosgene is the gas produced.