A toxicologist is presented with a hypothetical scenario: two men are found dead in an apartment. Autopsy results show carboxyhemoglobin levels of 72% and 74% — clearly lethal concentrations consistent with carbon monoxide poisoning. However, an independent experiment conducted in the same apartment, using the same heater under replicated conditions, shows that the heater cannot produce enough carbon monoxide to achieve those blood levels, and the apartment's oxygen concentration remained at 18.8% — well above the lethal threshold. The toxicologist is asked: is there any substance that, when administered to a living person, would produce elevated carboxyhemoglobin levels indistinguishable from carbon monoxide exposure in a standard autopsy, even if the person was never exposed to carbon monoxide gas? Name the class of compound and one specific example.