Final answer:
Precautions should be taken when using complex phenols for disinfection because they are corrosive and can cause severe burns to the skin as well as systemic poisoning in the bloodstream.
Step-by-step explanation:
One reason for taking precautions when using complex phenols for disinfection is that they are corrosive (B). Phenols, including complex phenols, can cause severe burns when applied to the skin, and in the bloodstream, they are systemic poisons that can affect all parts of the body. Historically, the effectiveness of chemical disinfectants has been compared to that of phenol (A), using the phenol coefficient as a measure. A disinfectant with a phenol coefficient greater than 1.0 is more effective than phenol.
Phenolics like hexachlorophene and o-phenylphenol are stable, long-acting disinfectants that denature proteins and disrupt cell membranes, and could be found in various products from hospital disinfectants to household cleaners and even used for preserving harvested crops. However, due to their toxic effects to humans and corrosive characteristics, it is crucial to handle them with care, especially in clinical settings where they are often used on surfaces like doorknobs to prevent microbial transmission.