9.6 Laboratory Safety: Bloodborne Pathogens, Personal Protective Equipment & Chemical Hygiene
Key Takeaways
- Standard Precautions treat all blood and body fluids as infectious and supersede the narrower Universal Precautions; clinical hematology operates at Biosafety Level 2 with Class II biological safety cabinets for aerosol-generating work.
- The hepatitis B vaccine must be offered free within 10 working days of assignment; declining employees sign a declination form and may accept vaccination later, and employee exposure medical records are kept for employment plus 30 years.
- Personal protective equipment is the LAST line of defense after engineering and work practice controls; gloves are removed first when doffing because they are the most contaminated item, and the mask or respirator is removed last.
- Safety data sheets follow a fixed 16-section GHS format and must be readily accessible in the work area on every shift; GHS labels use the signal words Danger (more severe) and Warning (less severe).
- In the NFPA 704 diamond, blue is health, red is flammability, yellow is instability, and white carries special symbols such as OX for oxidizer; chemicals are stored by compatibility group, and acid is always added to water.
Laboratory Safety: Bloodborne Pathogens, Personal Protective Equipment & Chemical Hygiene
The ASCP BOC lists safety programs and practices, prevention of bloodborne pathogen infection, personal protective equipment, safe work practices, and safety data sheets as distinct sub-topics. Safety items are rule-based and are among the most reliably scored questions on the examination.
1. The OSHA Bloodborne Pathogens Standard (29 CFR 1910.1030)
The standard is built on a written Exposure Control Plan that is reviewed and updated at least annually and whenever new procedures or devices are introduced. Its required elements are:
- Standard Precautions. All human blood and body fluids are treated as infectious for HIV, hepatitis B, and hepatitis C regardless of the patient's known status. This superseded the older term Universal Precautions, which addressed blood and a limited list of fluids; Standard Precautions extends to all body fluids, secretions, and excretions except sweat.
- Hepatitis B vaccination must be offered free of charge within 10 working days of assignment to a position with occupational exposure. An employee who declines must sign a declination form and may accept vaccination later at any time.
- Engineering controls: sharps disposal containers that are closable, puncture-resistant, leak-proof, and labeled; self-sheathing needles and safety-engineered devices; splash shields; Class II biological safety cabinets; and centrifuge safety cups.
- Work practice controls: no recapping of needles by hand, no eating, drinking, smoking, applying cosmetics, or handling contact lenses in work areas, no mouth pipetting, and hand hygiene immediately after glove removal.
- Annual training at no cost during working hours, plus retraining when tasks change.
- Recordkeeping: the sharps injury log, and employee medical records retained for the duration of employment plus 30 years; training records retained for 3 years.
Biosafety Levels
| Level | Agents | Practices |
|---|---|---|
| BSL-1 | Agents not known to cause disease in healthy adults | Standard microbiological practice, open bench |
| BSL-2 | Agents of moderate hazard, including HIV, HBV, HCV, Salmonella | The level at which clinical hematology operates: limited access, biohazard signage, Class II biological safety cabinet for aerosol-generating work, autoclave available |
| BSL-3 | Agents transmitted by inhalation, such as Mycobacterium tuberculosis | Directional inward airflow, sealed room, respiratory protection |
| BSL-4 | Dangerous agents with no treatment, such as Ebola virus | Positive-pressure suit, dedicated facility |
2. Personal Protective Equipment
PPE is the last line of defense, used after engineering and work practice controls. The employer must provide, launder, repair, replace, and dispose of it at no cost to the employee.
| Item | Requirement |
|---|---|
| Gloves | Worn for all specimen handling; changed between patients and whenever compromised; never washed and reused; latex-free alternatives available for sensitized staff |
| Laboratory coat / gown | Fluid-resistant, long-sleeved, with a closed front and knit cuffs; removed before leaving the laboratory and never taken home for laundering |
| Face protection | Goggles or a full face shield with a mask whenever splashes, sprays, or aerosols are possible, including opening evacuated tubes, uncapping specimens, and body fluid processing |
| Respiratory protection | An N95 or higher respirator requires fit testing and medical clearance; used for suspected airborne agents |
Sequence. Don gown, then mask or respirator, then goggles or face shield, then gloves. Remove gloves first, then goggles or face shield, then gown, then mask or respirator, performing hand hygiene immediately afterward. Gloves come off first because they are the most contaminated item.
3. Chemical Hygiene, Labeling & Safety Data Sheets
The Chemical Hygiene Plan
Required by the OSHA Laboratory Standard (29 CFR 1910.1450), it documents standard operating procedures, exposure controls, chemical fume hood use and monitoring, employee information and training, medical consultation, and designation of a Chemical Hygiene Officer.
Safety Data Sheets
Under the Globally Harmonized System (GHS), the old Material Safety Data Sheet was replaced by the Safety Data Sheet (SDS) with a fixed 16-section format in a defined order (identification; hazard identification; composition; first-aid; firefighting; accidental release; handling and storage; exposure controls and personal protection; physical and chemical properties; stability and reactivity; toxicological information; ecological; disposal; transport; regulatory; other). An SDS must be readily accessible to employees at all times during every shift, in the work area, without needing a password or a supervisor. GHS container labels carry a product identifier, signal word (Danger for the more severe hazard, Warning for the less severe), hazard and precautionary statements, pictograms, and supplier information.
NFPA 704 Fire Diamond
Used for stationary storage, not for shipping.
| Quadrant | Colour | Meaning | Scale |
|---|---|---|---|
| Left | Blue | Health hazard | 0 (none) to 4 (deadly) |
| Top | Red | Flammability | 0 to 4 |
| Right | Yellow | Instability / reactivity | 0 to 4 |
| Bottom | White | Special hazards: OX oxidizer, W with a slash for water-reactive, SA simple asphyxiant | Symbols, not numbers |
Chemical Storage and Handling
Store by compatibility group, not alphabetically: separate acids from bases, oxidizers from flammables and organics, and cyanides and sulfides from acids (which release lethal hydrogen cyanide and hydrogen sulfide gas). Flammables above the permitted bench quantity belong in an approved flammable-storage cabinet, and corrosives are stored below eye level. When diluting, always add acid to water; the reverse generates enough localized heat to boil and spatter concentrated acid.
A newly hired technologist begins work in hematology. What does the OSHA Bloodborne Pathogens Standard require regarding hepatitis B vaccination?
Personal protective equipment is being removed after processing body fluids. Which sequence is correct and why?
A container in the reagent storeroom bears an NFPA 704 diamond with 3 in the blue quadrant, 0 in the red quadrant, 1 in the yellow quadrant, and the letters OX in the white quadrant. How should this be interpreted?
Which statement about safety data sheets under the Globally Harmonized System is correct?