when should hands be washed select all that apply lab safety

"When & Why to Wash Hands: Essential Lab Safety Guide"

By David YoungMay 1, 2026

In the realm of laboratory safety, hand hygiene plays a pivotal role in preventing the spread of contaminants and maintaining a sterile environment. But when should hands be washed in a lab setting? The answer isn't as straightforward as you might think. It depends on various factors, including the type of experiment, the potential hazards involved, and the standard operating procedures (SOPs) of your lab. Let's delve into the intricacies of hand washing in lab safety, exploring when and why it's crucial to clean those mitts.

Understanding the Importance of Hand Hygiene in Labs

Before we discuss when to wash your hands, it's essential to understand why hand hygiene is so critical in a lab setting. Labs are teeming with potential hazards, from chemicals to biological agents. Your hands, being the primary mode of contact with these hazards, can easily transfer contaminants from one surface to another, compromising the integrity of your experiments and posing health risks to you and your colleagues.

When Should Hands Be Washed? Select All That Apply

Now, let's get to the heart of the matter. Here are some situations where you should wash your hands:

a poster with instructions to wash hands and how to use it for handwashing

a hand rub procedure poster with instructions on how to wash hands and help them properly

Before Starting Work: Begin your lab session with clean hands. This helps prevent any contaminants from your skin or under your nails from entering your workspace or samples.
After Handling Contaminants: If you've been handling chemicals, biological samples, or other hazardous materials, wash your hands immediately afterwards. This includes after using personal protective equipment (PPE) like gloves.
After Coughing, Sneezing, or Blowing Your Nose: Respiratory secretions can contain harmful microorganisms. Always wash your hands after tending to your nose or mouth.

After Eating or Drinking: Food and drinks can contain bacteria that could contaminate your workspace or samples. Always wash your hands before and after consuming food or beverages in the lab.

After Using the Restroom: Hands should be washed thoroughly after using the restroom to remove any bacteria or other contaminants.

After Handling Money or Other Commonly Touched Surfaces: Cash, doorknobs, and other shared surfaces can harbor bacteria. Washing your hands after touching these can help prevent contamination.

Hand Washing Technique

Washing your hands is not just about running them under water. To effectively remove germs and contaminants, follow these steps:

Wet your hands with clean, running water (warm or cold), turn off the tap, and apply soap.

Lather your hands by rubbing them together with the soap. Lather the backs of your hands, between your fingers, and under your nails.

Scrub your hands for at least 20 seconds. Need a timer? Hum the "Happy Birthday" song twice.

Rinse your hands well under clean, running water.

Dry your hands using a clean towel or air dry them.

When in Doubt, Wash

If you're unsure whether to wash your hands, it's always better to err on the side of caution. Frequent hand washing is a simple, yet powerful tool in maintaining a safe and sterile lab environment. So, keep those hands clean, folks!

Remember, Hand Sanitizers Aren't a Substitute

While hand sanitizers are convenient and can kill many types of germs, they are not a substitute for washing with soap and water. Hand sanitizers do not eliminate all types of germs, and many hand sanitizers contain high levels of alcohol, which can be harmful if ingested or absorbed through broken skin. Always follow your lab's SOPs for hand hygiene.