D. toxic substances that are known to have poisonousphysiological effects. The most common toxic gasesencountered are carbon monoxide and hydrogen sulfide. Carbon dioxide is a by-product of fermentationwhich displaces oxygen. Carbon monoxide is created by internal combustion. It can kill by replacing the oxygen in the bloodcausing unconsciousness.
Sulfur dioxide has a sharp pungent smell that istoxic in small amounts.
Hydrogen sulfide is part of many industrialprocesses that can cut off breathing once it enters the body. In higherconcentrations it can paralyze the sense of smell so its odor is notdetected. This may not be enough oxygen to supply the employee'srespiratory needs when performing physical work. 2. poor space design . The odd shapes such as slopingsides, a floor that tapers to a small section, or a confusing internal shapecould cause a person to become trapped and possibly cause suffocation.