Final answer:
The active chemical used for sterilization in a Steris unit is peracetic acid. It is preferred due to its rapid action and the breakdown into safe compounds. Glutaraldehyde and hydrogen peroxide are also utilized in different sterilization contexts.
Step-by-step explanation:
The active chemical used for sterilization in a Steris unit is peracetic acid. Steris units use this chemical because peracetic acid has a rapid action against microbial life including endospores and is less prone to inactivation by organic load. It breaks down into environmentally safe compounds, making it an ideal sterilant for a variety of medical and surgical instruments.
The effectiveness of chemical disinfectants has historically been compared to that of phenol. Glutaraldehyde, another chemical used for sterilization, is similar to formaldehyde but has two aldehyde groups for quicker action and is less frequently used as an antiseptic due to skin irritation. Hydrogen peroxide, widely used as a household disinfectant, is also employed in sterilization processes, often in the form of vaporized hydrogen peroxide (VHP).