Carbonyl sulfide is the most abundant sulfur compound naturally present in the atmosphere, at 0.5±0.05 ppb, because it is emitted from oceans, volcanoes and deep sea vents.

[5] The long atmospheric lifetime of COS makes it the major source of stratospheric sulfate, though sulfur dioxide from volcanic activity can be significant too.

[5] Carbonyl sulfide is also removed from the atmosphere by terrestrial vegetation by enzymes associated with the uptake of carbon dioxide during photosynthesis, and by hydrolysis in ocean waters.

The largest man-made sources of carbonyl sulfide release include its primary use as a chemical intermediate and as a byproduct of carbon disulfide production; however, it is also released from automobiles and their tire wear,[9] coal-fired power plants, coking ovens, biomass combustion, fish processing, combustion of refuse and plastics, petroleum manufacture, and manufacture of synthetic fibers, starch, and rubber.

A laboratory synthesis entails the reaction potassium thiocyanate and sulfuric acid: The resulting gas contains significant amounts of byproducts and requires purification.

[22] Hydrolysis of isothiocyanates in hydrochloric acid solution also affords COS. As of 1994, limited information existed on the acute toxicity of carbonyl sulfide in humans and in animals.

[14] Limited studies with laboratory animals also suggest that continued inhalation of low concentrations (around 50 ppm for up to 12 weeks) does not affect the lungs or the heart.