Medical Lab Science: Lab Safety

Lab Safety Introduction

• Lecture 17 focuses on lab safety in medical laboratory sciences
• Lindsey Clark is the primary instructor and has a background in occupational and environmental health, particularly lab safety

Objectives of the Lecture

• Recognize safe practices in the laboratory
• List the agencies that regulate laboratory safety
• Describe requirements for laboratory safety as outlined in OSHA’s blood-borne pathogen standards
• Identify common safety equipment, primary barriers, and secondary barriers utilized in the laboratory
• Compare and contrast biosafety levels and properly classify biohazardous agents

Topics Included in Lab Safety

• General lab safety guidelines
• Fire safety
• Chemical safety
• OSHA's blood-borne pathogen standard
• Biosafety, including standard microbiological practices, biosafety levels, and biosafety cabinets

Agencies Regulating Lab Safety

• OSHA (Occupational Safety and Health Administration)
• CDC (Centers for Disease Control and Prevention)
• State Department of Health (e.g., Arkansas Department of Health)
• CAP (College of American Pathologists) or other accrediting agencies
• The Joint Commission

General Safety Guidelines: Hand Hygiene

• Hand hygiene is crucial for preventing the spread of infection
• Wash hands frequently, especially after removing gloves, when hands are visibly soiled, and before leaving the lab
• Remove gloves, then lab coat, before washing hands to avoid recontamination

General Safety Guidelines: Food and Drink

• No food, drink, smoking, or cosmetics in the lab including lip balm
• Food must be stored outside the lab in designated areas like break rooms
• Check refrigerators in point-of-care testing sites for inappropriate storage of food next to specimens

General Safety Guidelines: Pipetting and Sharps

• No mouth pipetting is allowed; use available pipetting devices
• Labs must have a policy for safe handling and disposal of sharps (needles, scalpels, Pasteur pipettes)
• All procedures should minimize the creation of aerosols
• Perform aerosol-generating procedures in a biosafety cabinet

General Safety Guidelines: Disinfection

• Disinfect workspaces frequently: at the start of the shift, after spills, and at the end of the shift
• Use appropriate disinfectants for surfaces and equipment touched by gloved hands (keyboards, mice, phones)

General Safety Guidelines: Dress Code

• Tie hair back, especially long hair
• Wear closed-toe shoes made of non-porous material (leather or patent leather preferred)
• No shorts or skirts; wear long pants
• Wear a buttoned-up lab coat and gloves when processing specimens or handling infectious materials or harmful reagents
• Follow specific PPE guidelines for each procedure

Fire Safety: RACE

• RACE: Rescue, Alarm, Contain, Extinguish/Evacuate
• Rescue: Remove patients or coworkers from danger
• Alarm: Pull the fire alarm
• Contain: Close doors to contain the fire
• Extinguish: If safe, extinguish the fire; otherwise, evacuate

Fire Safety: Evacuation and PASS

• In case of fire, do not use elevators; close doors while evacuating
• Evacuate vertically, then horizontally if possible
• PASS: Pull, Aim, Squeeze, Sweep (for using a fire extinguisher)
• Pull the pin, aim the nozzle at the base of the fire, squeeze the handle, and sweep the nozzle back and forth

Fire Safety: Prevention and Awareness

• Know the location of fire extinguishers, types of extinguishers, and the lab's evacuation route
• Prevent fires by keeping flammables away from heat and treating chemicals with respect
• Turn off or unplug equipment before attempting repairs; if there's a smell of smoke, unplug safely, leave, and report it

NFPA Hazard Identification Label

• Used for quick identification of hazards, especially for emergency responders
• Consists of four color-coded fields:
  • Red: Fire hazards
  • Blue: Health hazards
  • Yellow: Stability/reactivity
  • White: Specific hazards (corrosive, radioactive, etc.)
• Numbering scale from 0 to 4: 0 is non-hazardous, 4 is most hazardous
• Opposite numbering scale compared to the Globally Harmonized System (GHS)

Chemical Safety: Chemical Hygiene Plan

• Each lab must have a chemical hygiene plan, including safety data sheets (SDS) for each chemical and training documentation
• Training is required initially upon hire (before working with chemicals) and annually thereafter

Chemical Safety: Right to Know Standard

• Employees have the right to know and understand the hazards they may be exposed to while working with chemicals
• Employers must provide information through a written program, chemical labeling, SDS access, and training

Chemical Safety: Employee Responsibility and Chemical Classes

• Employees should seek specific information about chemicals
• SDS (Safety Data Sheets) are now stored online
• Pregnant or immunocompromised individuals working with chemicals should take extra precautions
• Flammable and corrosive chemicals require special containers

Chemical Safety: Storage and Handling

• Treat all chemicals as potentially toxic
• Store chemicals in well-ventilated areas
• Store acids and bases separately
• Store flammables in a flammable storage cabinet (usually yellow with red writing)
• Transport more than 1,000 mL of a chemical on a cart
• Dispose of chemicals properly, not down the drain

Chemical Safety: Fume Hoods and Labeling

• Handle flammables and fuming chemicals in a fume hood
• All chemical containers must be properly labeled, including secondary containers
• Labels should include the chemical name (not abbreviations), concentration, and hazard warnings

Chemical Safety: Emergency Equipment

• Eyewash station and emergency shower must be available in the lab
• Accrediting agencies check for these and their maintenance logs
• Maintenance logs must be up-to-date

Globally Harmonized System (GHS)

• Developed by the United Nations to standardize chemical classification and labeling
• OSHA revised its Hazard Communication Standard in 2012 to incorporate the GHS
• Affects safety data sheets, labeling, and pictograms

GHS: Safety Data Sheets (SDS)

• Standardized into 16 sections with a strict ordering
• Replaced Material Safety Data Sheets (MSDS)
• Standardized format helps with quickly finding information in emergencies

GHS: Labels and Pictograms

• Standardized labels include pictograms for physical hazards, health hazards, and environmental hazards
• Pictograms communicate across languages
• Example: skeleton for acute toxicity

Blood-borne Pathogen Standard: Requirements

• Standard mandates every lab have a written program to protect workers from health hazards related to blood-borne pathogens
• Exposure control plan: a written policy outlining protective measures to eliminate or minimize employee exposure to blood or Other Potentially Infectious Materials (OPIM)

Blood-borne Pathogen Standard: Exposure Control Plan Components

• Employee exposure determination
• Methods of implementation and control
• Hepatitis B vaccination requirements
• Exposure evaluation and follow-up procedures
• Procedures for evaluating the circumstances surrounding an exposure incident
• Documentation for employee training

Blood-borne Pathogen Standard: Employee Exposure Determination

• Outlines job classifications with occupational exposure risk
• Lists job classifications where all employees have exposure risk (e.g., lab workers)
• Lists job classifications where only some workers have exposure risk (e.g., environmental services)
• Specifies job tasks that could result in exposure for those in job classifications with partial exposure risk

Blood-borne Pathogen Standard: Implementation and Review

• Exposure control plan details how the employer keeps employees safe
• The plan can be included in the lab safety manual
• Must be reviewed annually or if any changes occur
• Focus on biosafety, more relevant but the practices can apply to the whole lab

Biosafety Resources

• CDC’s "Biosafety in Microbiological & Biomedical Laboratories" (BMBL), known as the "Bimble"
• NIH guidelines for research involving recombinant or synthetic nucleic acid molecules. This applies to research labs involved in recombinant DNA

Standard Microbiological Practices for Biosafety Level 1

• Restrict or limit access to the lab
• Door signs are required, especially in research and micro labs, noting biohazard areas and required PPE
• Wash hands
• No eating, drinking, smoking, etc.
• No mouth pipetting
• Sharps policies are required
• Minimize aerosols
• Decontaminate before disposal (microbiological cultures)
• Pest management plan must be in place
• Required training must be completed and documented

Biological Safety Cabinets (BSCs)

• Engineered to protect personnel and the environment
• Class 2 and Class 3 cabinets also protect the product (specimen or culture)
• All BSCs use a HEPA filter (high-efficiency particulate air filter)
• All cabinets must be inspected and certified annually

BSC Classification

• Three classes of cabinets: Class 1, Class 2, and Class 3
• Most clinical labs have a Class 2 BSC
• Class 1: Protection to personnel and the environment but not products
• Class 2: Protection to products, personnel, and environment
• Class 3: Fully enclosed, often with gloveboxes, for BSL-3 or -4

Class 2 BSC Subtypes

• Subdivided into Class 2 Type A, Class 2 Type B1, and Class 2 Type B2
• Differences lie in the amount of air recirculated and airflow speed
• Airflow is carefully designed:
  • Room air is pulled in through the front grate, runs under the workspace, and up the sides.
  • Polluted air from inside the cabinet is also pulled in through the grate.
  • Air is pushed through a HEPA filter and back into the cabinet or exhausted out.
• Vital to keep the grate clear to maintain efficiency

Biosafety Levels (BL1 to BL4)

• BL1 represents the lowest risk, with agents of minimal hazard (e.g., non-toxin-producing E. coli)
• BL2 poses a slightly higher risk (Salmonella, Lyme disease); some procedures may require a cabinet
• BL3 includes agents that pose a serious risk if infected (Brucella, TB)

Biosafety Levels

• There is one Biosafety Level 3 (BL3) research lab at UAMS.
• The Arkansas Public Health lab also has a BL3 lab.
• BL3 labs are uncommon in Arkansas; if there are others, there are very few.
• Biosafety Level 4 (BL4) labs represent the highest risk and handle the most dangerous organisms, such as Ebola and Marburg viruses.
• Working with organisms in a BL4 lab requires a full suit with positive air pressure and maximum containment areas.

Arkansas BL4 Lab Status

• The state of Arkansas does not have a BL4 lab.
• Absence of a BL4 lab indicates their rarity.

Brucella Handling

• Microbiology labs should handle cultures with suspected Brucella under a hood, if Brucella growth from a wound culture is suspected.
• If certain Brucella species are ruled out and a special agent is suspected, stop working with the culture.
• Send suspicious cultures to the public health lab for identification or confirmation, rather than using Vitek or MALDI-TOF mass spec due to aerosolization risks.
• Improper handling leading to aerosolization can result in lab personnel undergoing routine testing and prophylactic treatment.

Safety Equipment and Barriers

• Safety equipment includes personal protective equipment (PPE) like gloves, coats, face shields, and goggles.
• Primary barriers are engineering controls that minimize exposure to hazardous biological materials.
• Primary barriers include biosafety cabinets, closed containers for transporting specimens, and centrifuge safety cups.
• Secondary barriers are created through facility design and construction to protect lab workers, the public, and the community from infectious agents.
• Examples of secondary barriers include restricted lab access, special ventilation, air treatment systems, and separate buildings.
• Public health labs working with biohazard agents may use separate, nondescript buildings to prevent access to bioterrorism agents.

BMBL Reference

• The Biosafety in Microbiological and Biomedical Laboratories (BMBL) can be downloaded from the CDC website.
• The BMBL provides detailed regulations and information on safety practices.

Safety Emphasis

• Adhering to safety guidelines in the lab can significantly reduce the chances of exposure or accidents.
• A reminder: Do not put dry ice down the sink or play with it, due to safety hazards.