1: Lab Safety

Last updated

Mar 13, 2025
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- Licensing
- 2: Basic Lab Equipment

Kari Christenson, Western Technical College

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Learning Objectives

Course Competency: Adhere to safety and infection control policies

Learning Objectives:

Explain physical safety policies
Explain chemical safety policies
Adhere to biological safety policies
Practice infection control

Introduction

Laboratory safety involves all the measures taken by the laboratory worker, institution, and regulatory agencies to eliminate potential harm to human health and well-being. Although steps are taken to reduce risks in the workplace, safety is a matter of personal responsibility. A clinical lab may have several safety hazards that must be known and understood by all students or employees working in the lab. It is the responsibility of each person in the lab to know and follow basic laboratory safety rules, to understand how to safely operate equipment, understand the hazards of materials they are working with and to work to reduce potential risks. In the event of an accident, it is critical to know the location and use of emergency equipment. Having this knowledge should help to prevent accidents and minimize damage that might occur in the event of an accident.

OSHA - It's the Law¹

Creating a safe laboratory workspace is required by law. The federal government regulates safety within the workplace thru OSHA, the Occupational Safety and Health Administration. The regulations are designed to inform workers about hazards they may encounter and protect workers from harm. This is called OSHA’s Hazard Communication Standard.² Employers must provide safety training, proper safety apparel, and a safe work environment.

Personal Protective Equipment (PPE)³

Employers must provide Personal Protective Equipment (PPE) to protect employees. PPE includes face, eye and skin protection, fume hoods, and gloves to protect the skin of the hands.

Categories of Hazards

Hazards within the laboratory can be divided into physical hazards, chemical hazards, and biological hazards.

Physical Hazards

Physical hazards include electrical and fire safety. Before servicing any equipment, it should be unplugged. Circuits should not be overloaded, and the use of extension cords should be avoided. Fire safety includes storing flammable chemicals in a flameproof cabinet, knowing your facilities escape plan, and the location of fire alarms and extinguishers.

Lab Safety Equipment: Fire Extinguishers⁴

Portable fire extinguishers apply an extinguishing agent that will either cool burning fuel, displace or remove oxygen, or stop the chemical reaction so a fire cannot continue to burn. When the handle of an extinguisher is compressed, agent is expelled out the nozzle.

Most fire extinguishers operate using the following P.A.S.S. technique:

PULL... Pull the pin. This will also break the tamper seal.
AIM... Aim low, pointing the extinguisher nozzle (or its horn or hose) at the base of the fire.
SQUEEZE... Squeeze the handle to release the extinguishing agent.
SWEEP... Sweep from side to side at the base of the fire until it appears to be out. Watch the area. If the fire re-ignites, repeat steps 2 - 4.

If you have the slightest doubt about your ability to fight a fire, evacuate immediately!

Figure $\PageIndex{2}$ : Portable Fire Extinguisher. (Copyright Occupational Safety and Health Administration, U.S. Department of Labor; Public Domain)

Chemical Hazards

Chemical hazards are another kind of hazard within the laboratory. OSHA mandates the use of a written safety plan for hazardous chemicals. This is called the Chemical Hygiene Plan. The Hazard Communication Standard also mandates the use of Safety Data Sheets (SDS) and Hazard Communication Standard (HCS) Labels to communicate information to the user about chemical hazards.

Safety Data Sheets (SDS): A Safety Data Sheet (previously called Material Safety Data Sheet) for each chemical is required by the Occupational Safety and Health Administration (OSHA). Sections 1-8 contain information about the identification, hazards, composition, safe handling practices, and emergency control measures. Sections 9 through 11 and 16 contain technical and scientific information, such as physical and chemical properties, stability and reactivity, toxicology, and exposure control.

Hazard Communication Standard (HCS) Labels: A quick assessment of a chemical’s hazards is visible on its container on a Hazard Communication Standard (HCS) label. HCS labeling does not replace the more detailed Safety Data Sheet (SDS) but rather gives the following information in brief:

Name, Address, and Phone Number of Responsible Party (i.e., the manufacturer or distributor)
Chemical Identification - chemical name and code or batch number that matches the information found in Section 1 of the chemical's SDS
Signal Word - "DANGER" for more severe hazards or "WARNING" for less severe hazards
Hazard Statements - a brief description of the hazard(s)
Precautionary Statements (optional) - prevention, response, storage, and disposal
Hazard Category Numbers 1-4 (optional) - "1" for the most severe hazard to "4" for the least severe
Pictograms

Pictograms are red-bordered, diamond shapes that frame a black graphic on a white background, and these symbols depict the type of hazard(s). HCS labels are required by the Occupation Safety and Health Administration (OSHA) and are standardized, having been adopted from the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) set by the United Nations.

Table 1. HCS Pictogram Guide


Hazard Class	Hazard Type	Example Signal Word & Hazard Statement
Flammables Self-Reactives Self-Heating Pyrophorics Emits Flammable Gas Organic Peroxides	Physical	DANGER Heating may cause a fire
Explosives Self-Reactives Organic Peroxides	Physical	WARNING Fire or projection hazard
Gases Under Pressure	Physical	WARNING Contains gas under pressure; may explode if heated
Corrosive to Metals Corrosive Skin Corrosion/Burns Eye Damage	Physical Health	DANGER Causes severe skin burns and eye damage
Oxidizer (gases) Oxidizers (solid or liquid)	Physical Health	WARNING May intensify fire; oxidizer
Acute Toxicity (fatal or toxic)	Health	DANGER Fatal if swallowed
Carcinogen Mutagenicity Respiratory Sensitizer Reproductive Toxicity Target Organ Toxicity Aspiration Toxicity	Health	DANGER May cause cancer
Irritant (skin and eyes) Dermal Sensitizer Acute Toxicity (harmful) Narcotic Effects Respiratory Tract Irritation Hazardous to Ozone Layer (optional)	Health Other	WARNING Causes skin irritation
(optional label) Environmental Toxicity Aquatic Toxicity	Environment.	WARNING Toxic to aquatic life

National Fire Protection Association (NFPA) Hazard Rating System: The National Fire Protection Association (NFPA) Hazard Rating System was designed for emergency workers such as fire responders to be able to swiftly get basic information about the hazards of a chemical from a simple label. The diamond-shaped label is divided into four color-coded squares, and inside each square is printed a ratings code or number from 0-4, with "0" as the least severe hazard to "4" as the most severe.

Inside the red square, the number indicates the flammability rating; blue indicates the health hazard rating; yellow indicates the chemical's instability; and the white square indicates any special hazards.

complex image explaining the NFPA Hazard Rating System

Chemical Hazards and Waste Disposal: Laboratory waste must be disposed of safely and appropriately. Labs must be aware of the school, state and federal guidelines for waste disposal. Many chemicals can NOT be poured down the sink. Be sure you know which chemicals are hazardous, require special storage and must be placed into properly labeled waste containers kept in fume hoods until sent to the proper hazardous waste disposal. Know which materials are considered biohazards and the proper area or container to place them so they can be autoclaved.

Table 2. Medical and Biohazardous Waste Treatment and Disposal Chart, U. California
Type of Waste	Definition	Required Treatment
Chemical Waste	Any solid, liquid, or gaseous material generated in the laboratory that poses a danger to human health or the environment.	This will vary depending on the chemical. The institution you are in will have specific requirements to meet regulatory code. The aim is to reduce hazards and minimize environmental impact. Follow your instructor’s directions.
Solid Biohazardous Waste	Materials such as pipettes, petri dishes, or other culture flasks disposable or glass that do not contain liquid but were in contact with cultures of cells or human or animal-derived materials.	Disposable waste is placed in red biohazard bags. Treat and replace bags when they are halfway full. Reusable glass materials must be placed in autoclavable trays. To treat waste, the autoclave must be properly loaded and set for a minimum temperature of 121°C (250°F) for 60 minutes at 15 psi. Autoclave tape must be placed on the bag or tray to indicate it has passed through the cycle. Material should be autoclaved as soon as possible, but at a maximum of 7 days after it is generated
Liquid Biohazardous Waste	Broth cultures or cell culture media or contaminated liquid media.	Decontaminate using 10% bleach solution for a minimum 2 hours contact time. Dispose down the drain with water. Alternatively, racks of used culture tubes can be autoclaved using the same temperature and time indicated above but set for a slow exhaust liquid setting. Use autoclave tape as above. Treat waste as soon as possible but not longer than 7 days post generation.
Sharps Waste	Any object that is capable of piercing or damaging human skin that is contaminated with chemical, or biohazardous waste e.g., scalpels, blades, needles, broken glass, etc.	Place in the marked sharps container. Remember that broken glass that is not contaminated will have a separate disposal container within the laboratory.

Biological Hazards⁵

Biological hazards are the third kind of hazards within the laboratory environment. All human blood and other body fluids are treated as if they are infectious. This is applied universally to all patients, regardless of whether they are suspected of being infectious. OSHA’s Bloodborne Pathogens Standard⁶ outlines how to protect workers from bloodborne pathogens or other potentially infectious material (OPIM). Bloodborne pathogens are disease-causing microorganisms in human blood or OPIM. The standard requires the employer to train lab staff members who might be exposed to blood and/or OPIM.

Exposure is defined as contact with blood or OPIM at the eye, mucous membrane, or skin - including punctures, such as needlesticks. The Bloodborne Pathogens Standard specifies measures--such as careful handling of contaminated sharps--to reduce these types of injuries and the risk of infection.⁷

Dropping a needle into a sharps container — Figure $\PageIndex{3}$ : Sharps Disposal Container. (Copyright William Rafti via Wikimedia Commons; CC BY 2.5)

The three most common bloodborne pathogens are Hepatitis B virus (HBV), Hepatitis C virus (HCV), and Human Immunodeficiency virus (HIV).

Hepatitis B Virus (HBV)⁸ is spread through blood and other bodily fluids. HBC can cause serious harm to the liver, including:

Liver inflammation or disease (hepatitis) and/or liver cancer, even death
Acute (short-term) or chronic (long-term) liver infection
Cirrhosis of the liver and other serious liver diseases

Recovery from acute infection is possible, but chronic HBV infection requires medication. There is no known cure for HBV, but there is a vaccine that can protect against HBV and the severe consequences of hepatitis B infection.

People with HBV do not always have symptoms, so a blood test is important for diagnosis. Most infected persons who become HBV carriers are asymptomatic. However, asymptomatic HBV carriers can spread the virus to others.

People with HBV who do have symptoms may experience:

Jaundice or yellowing of the skin
Tiredness
Abdominal pain
Loss of appetite
Occasional nausea
Vomiting
Dark urine

Hepatitis C Virus (HCV)⁹ is spread through blood and other bodily fluids and is another member of the hepatitis virus family that:

Can cause liver inflammation
Causes liver disease and/or liver cancer
Can be acute (short term) or chronic (long term)

More than half the people who become infected with hepatitis C will develop a chronic illness.

HCV is curable with timely medical treatment, but there is no HCV vaccine.

Almost half of people who have HCV are unaware they have it, and many people with HCV don't have symptoms. An asymptomatic person with HDV can spread it to others, so blood tests are important for diagnosis.

People with HCV who do have symptoms may experience:

Jaundice or yellowing of the skin
Tiredness
Abdominal pain
Loss of appetite
Occasional nausea
Vomiting
Dark urine
Flu-like symptoms

Human Immunodeficiency Virus (HIV)¹⁰ is spread through blood and other bodily fluids. HIV attacks and weakens the body's immune system, making it difficult to fight off common diseases and increasing the chances of developing severe infections or illnesses. Advanced stages of HIV can develop into acquired immunodeficiency syndrome (AIDS).

Many tests are available to diagnose HIV, but there is no vaccine for HIV. There is no cure for HIV or AIDS, although long-term drug therapy can control the disease.

A person can carry HIV for many years without symptoms. HIV might or might not develop into AIDS. Without treatment, people with AIDS typically survive about three years.

Early HIV symptoms resemble flu-like symptoms, including fever, chills, and body aches.

After the virus multiplies in the body, the following symptoms might occur:

Swollen lymph nodes
Fatigue
Diarrhea
Persistent fever
Persistent dry cough

Laboratory Safety Guidelines

General Rules:

No guests are allowed in the lab.
Know emergency procedures, use and location of emergency equipment (emergency exits, fire extinguishers, fire blanket, eye wash station, first aid kit, and broken glass container).
In case of fire, evacuate the room and assemble outside the building.
Report all accidents, no matter how insignificant they appear, to a laboratory supervisor
Be aware of your surroundings and potential dangers created by others.

Personal Protection:

Do not smoke, eat, drink, chew gum, or apply cosmetics in a laboratory. Food and drink cannot be stored in lab refrigerators.
When handling hazardous chemicals, blood, body fluids, or other potentially hazardous/contaminated material, wear protective clothing such as long pants, closed-toe and heel shoes, a lab coat, safety glasses, and gloves.
Shoes should be closed-toe and heel with a slip-resistant tread pattern.
Gloves will be worn when having contact with hazardous chemicals, blood, or other potentially infectious materials; when collecting blood specimens; when touching contaminated items or surfaces. Discard gloves if torn, punctured, or contaminated.
Safety glasses or goggles are required when splashes, sprays, or droplets of blood, other infectious materials, or hazardous chemicals may be generated.
Face shields are required when mixing or pouring hazardous or toxic chemicals.
Countertop shields can be used in place of face shields when opening blood tubes or when sprays or splashes may be generated.
Lab coats, which are impervious to blood (may be disposable) and body fluids, are required when working in the laboratory. The coats must be snapped closed for complete protection. Lab coats must be replaced if torn or contaminated.
Lab coats may not be worn outside of the immediate work area (hallway, restroom, etc.).
Tie long hair up or back behind the shoulders.
Do not wear long, dangling jewelry or scarfs.
Cover cuts or scrapes with a sterile, waterproof bandage before entering a lab.
Wash hands before and after any laboratory procedure, before leaving laboratory, after removing gloves, and after contamination.
All work surfaces must be decontaminated after completion of procedures, after any spill of potentially infectious material, and at the end of each lab session.
Let your lab instructor know before leaving the classroom.

Handling Chemicals and Potentially Infectious Materials:

Label all reagents and other chemicals clearly with the contents, date of receipt or preparation, and expiration date if applicable.
Read labels carefully. Be aware of hazardous chemicals and precautions for safe use.
Keep all containers capped with the appropriate lid.
Follow all safety procedures for cleaning up spills, splashes, and broken glass. Use broom and duspan to pick up broken glass.
Blood specimens and other potentially infectious materials must be disposed of in proper containers.
Follow instructions about proper disposal of lab reagents.

Handling Equipment:

Keep your work area clean and free of unnecessary clutter and personal belongings.
Follow manufacturer's instructions for all equipment operation and maintenance.
Do not use laboratory equipment without first receiving instruction in its use.
Notify lab supervisor of malfunctioning equipment.
Use the biological safety or fume hood as the procedure requires.
Contaminated sharps are placed in appropriate sharps containers. Recapping of needles is prohibited.

Additional Laboratory Safety Equipment

Fume Hood¹¹

The fume hood is often the primary control device for protecting laboratory workers when working with flammable and/or toxic chemicals.

Laboratory Safety Chemical Fume Hoods — Figure $\PageIndex{4}$ : Chemical Fume Hood. (Copyright Occupational Safety and Health Administration, U.S. Department of Labor; Public Domain)

Eyewash Station¹²

If your nose, mouth, or eyes have been exposed to blood or body fluids, follow the steps below:

Rinse the affected area with large amounts of water or saline solution for several minutes.
If running water is not available, use another source of water to rinse, such as bottled water.

Figure $\PageIndex{5}$ : Eyewash Station. (Copyright U.S. Centers for Disease Control and Prevention; Public Domain)

Infection Control

Healthcare-associated infections are those that are acquired in a health care setting by health care workers or patients. The infection control department within healthcare settings works to lower the incidence of these types of infections.

Chain of Infection Components¹³

They include:

Microorganisms: Disease producing, also called pathogens
- Virus, parasite, fungus, bacterium
- Risk factors: Virulence, pathogenicity, ability to enter host
Reservoir/Source: Environment/habitat where a pathogen can live and multiply
- Environmental surfaces/equipment, body fluids (blood, saliva), urine/fecal material, food/water, soil, skin, respiratory tract
Portal of Exit: How the pathogen exits or leaves reservoir
- Skin to skin, skin to surface, blood, mucous membranes, oral cavity, fecal
- Other potentially infectious material (OPIM): Seminal fluid, joint fluid, saliva, urine/fecal material, any body fluid contaminated with blood
Modes of Transport: How a pathogen moves from reservoir to susceptible host
- Direct Transmission: Airborne, droplet, contact (e.g., skin), bite, needlestick or other sharps injury
- Indirect Transmission: Fomites – contaminated equipment or medication, vectors, food, water
Portal of Entry: Opening where the pathogen may enter
- Body openings (e.g. mouth, eyes, urinary tract, respiratory tract), incisions, wounds
Susceptible Host: The person at-risk: patient or healthcare worker
- Factors affecting susceptibility (e.g. age, health, co-morbidities, immune system, nutrition, infective dose, medications)

Chain of Infection graphic — Figure $\PageIndex{6}$ : Chain of Infection. (Copyright The National Institute for Occupational Safety and Health; Public Domain)

To break the chain of infection, use standard precautions, hand hygiene, and wear PPE. Patients who are at risk of spreading or contracting infections can also be isolated. Isolation is the separation of an infection source from susceptible hosts. Reverse or protective isolation is used for immunocompromised patients.

Standard Precautions

Standard precautions must be applied to all patients, regardless of their suspected infection status. Precautions are applied to all body fluids, non-intact skin and mucous membranes.

Hand Hygiene¹⁴

Hand hygiene is the most effective way of preventing the spread of infection. Hand hygiene includes washing your hands with soap and water or rubbing your hands with an alcohol-based hand sanitizer.

If your hands have been exposed to blood or body fluids, follow the steps below:

Rinse the affected area with large amounts of water or saline solution for several minutes.
Apply soap and water liberally and vigorously scrub all surfaces of hands and fingers.
Rinse hands thoroughly and dry with disposable towels.
Use a disposable towel to turn off the faucet.