Biological Hazards and Mold

1. Why This Topic Matters

Biological hazards are one of the five classic categories of occupational health hazards recognized in industrial hygiene (alongside chemical, physical, ergonomic, and psychosocial hazards). On the BCSP Associate Safety Professional (ASP) exam, this topic appears within the Industrial Hygiene and Occupational Health domain and tests your ability to recognize, evaluate, and control exposures to living organisms and their byproducts.

Why it is important in practice and on the exam:
- Biological agents can cause infection, allergic reaction, toxic response, or cancer, and some have no safe threshold of exposure.
- Healthcare, laboratories, agriculture, wastewater treatment, food processing, building maintenance, and disaster response workers face routine biological exposure.
- OSHA regulates certain biological hazards directly (the Bloodborne Pathogens Standard, 29 CFR 1910.1030) and others indirectly through the General Duty Clause, the Respiratory Protection Standard, and the PPE Standard.
- Mold is one of the most common indoor environmental quality (IEQ) complaints a safety professional will be asked to investigate, and it is a frequent exam scenario because it integrates building science, moisture control, assessment, and remediation.
- The COVID-19 pandemic, Legionnaires disease outbreaks, and post-flood mold remediation have made biological hazard competency a core expectation for safety professionals.

2. What Biological Hazards Are

A biological hazard (biohazard) is any biological substance that poses a threat to the health of living organisms. In the workplace this includes:

Microorganisms
- Bacteria: Legionella (Legionnaires disease and Pontiac fever), Mycobacterium tuberculosis, Staphylococcus aureus (including MRSA), Clostridium tetani, Bacillus anthracis (anthrax), Leptospira.
- Viruses: Hepatitis B (HBV), Hepatitis C (HCV), Human Immunodeficiency Virus (HIV), influenza, SARS-CoV-2, rabies, hantavirus.
- Fungi: molds (Stachybotrys chartarum, Aspergillus, Penicillium, Cladosporium, Alternaria), Histoplasma capsulatum (histoplasmosis, associated with bird and bat droppings), Coccidioides (Valley fever, associated with soil disturbance in the Southwest US).
- Parasites and protozoa: Giardia, Cryptosporidium, hookworm.
- Prions: abnormal proteins (e.g., Creutzfeldt-Jakob disease).

Biological byproducts and allergens
- Endotoxins: components of gram-negative bacterial cell walls that cause fever, respiratory inflammation (relevant in cotton dust, grain dust, wastewater, and agricultural settings).
- Mycotoxins: toxic secondary metabolites produced by some molds (aflatoxin, trichothecenes, ochratoxin).
- Allergens: animal dander, dust mites, pollen, latex proteins, fungal spores, insect parts.
- Plant toxins: poison ivy urushiol, and others.

Vectors and animals
- Insects and arachnids (ticks carrying Lyme disease, mosquitoes carrying West Nile virus), rodents, bird and bat droppings, animal bites, venomous snakes and spiders.

Key definitions you should know
- Pathogen: an organism capable of causing disease.
- Zoonosis: a disease transmitted from animals to humans (rabies, anthrax, brucellosis, Q fever, avian influenza).
- Bloodborne pathogen: a pathogenic microorganism present in human blood that can cause disease; OSHA specifically names HBV, HCV, and HIV.
- Other Potentially Infectious Materials (OPIM): semen, vaginal secretions, cerebrospinal, synovial, pleural, pericardial, peritoneal, and amniotic fluids, saliva in dental procedures, any body fluid visibly contaminated with blood, unfixed human tissue, and HIV/HBV-containing cultures.
- Universal Precautions: treating all human blood and OPIM as if known to be infectious. (Standard Precautions, used in healthcare, expand this to all body fluids.)
- Occupational exposure: reasonably anticipated skin, eye, mucous membrane, or parenteral contact with blood or OPIM resulting from job duties.
- Infectious dose: the number of organisms needed to cause infection; varies widely by agent.
- Incubation period: time between exposure and onset of symptoms.
- Virulence: the degree of pathogenicity of an organism.

3. How Biological Hazards Work: Routes of Exposure and Transmission

Just like chemicals, biological agents enter the body by four principal routes:
1. Inhalation: airborne droplets, droplet nuclei (aerosols under about 5 micrometers that stay suspended), spores, and bioaerosols. This is the primary route for tuberculosis, Legionella, mold spores, and histoplasmosis.
2. Ingestion: hand-to-mouth transfer, contaminated food or water (Giardia, Hepatitis A, E. coli).
3. Dermal / mucous membrane contact: through broken skin, eyes, nose, mouth.
4. Injection / parenteral: needlesticks, sharps injuries, animal bites, insect bites (the dominant route for HBV, HCV, HIV in healthcare).

Transmission modes
- Direct contact: person-to-person touching, blood exposure.
- Indirect contact: via contaminated surfaces or objects (fomites).
- Droplet: large respiratory particles traveling short distances (roughly 1 to 2 meters).
- Airborne: small particles remaining suspended for long periods and traveling on air currents (TB, measles). Airborne infection isolation rooms use negative pressure and at least 12 air changes per hour (6 for existing facilities) with HEPA filtration or direct exhaust.
- Vector-borne: insects or animals carrying the agent.
- Common vehicle: contaminated water or food (e.g., Legionella in cooling towers, hot water systems, decorative fountains).

The chain of infection
Infectious agent, reservoir, portal of exit, mode of transmission, portal of entry, susceptible host. Controls work by breaking any link in this chain. Exam questions often ask which control breaks which link (e.g., vaccination addresses the susceptible host; disinfection addresses the reservoir; a needleless system addresses the mode of transmission and portal of entry).

Health effects of biological exposure
- Infection: the organism multiplies in the body (TB, hepatitis).
- Allergic / hypersensitivity reaction: allergic rhinitis, asthma, hypersensitivity pneumonitis (farmers lung from moldy hay, humidifier fever).
- Toxic effect: from endotoxins or mycotoxins (organic dust toxic syndrome, grain fever).
- Irritant effect: microbial volatile organic compounds (MVOCs) produced by mold cause odors and irritation.
- Carcinogenic effect: HBV and HCV linked to liver cancer; aflatoxin is a known human carcinogen.

4. The OSHA Bloodborne Pathogens Standard (29 CFR 1910.1030)

This is the single most tested regulatory topic in biological hazards. Know these elements:

- Scope: applies to all employees with reasonably anticipated occupational exposure to blood or OPIM (not only healthcare: also first aid responders, housekeeping in certain settings, law enforcement, tattoo artists, laundry workers, body art, and some laboratory workers).
- Exposure Control Plan (ECP): written, accessible to employees, reviewed and updated at least annually and whenever tasks or procedures change. Must document consideration of safer medical devices (per the Needlestick Safety and Prevention Act of 2000) and solicit input from non-managerial frontline employees.
- Exposure determination: list of job classifications with exposure, made without regard to PPE use.
- Universal Precautions: required.
- Engineering controls: sharps disposal containers (closable, puncture-resistant, leakproof, labeled or color-coded), self-sheathing needles, needleless systems, handwashing facilities (or antiseptic hand cleanser/towelettes when not feasible). Engineering controls must be examined and maintained or replaced on a regular schedule.
- Work practice controls: no recapping, bending, or shearing of needles (recapping only by one-handed technique or mechanical device if required by a specific procedure); no eating, drinking, smoking, applying cosmetics, or handling contact lenses in work areas with exposure; no mouth pipetting; minimize splashing.
- PPE: provided at no cost, appropriate type and size, hypoallergenic alternatives for latex-sensitive workers, laundered or disposed of by employer. Gloves, gowns, face shields, masks, eye protection as needed.
- Housekeeping: written schedule for cleaning and decontamination; contaminated surfaces decontaminated with an appropriate disinfectant (EPA-registered tuberculocidal, or a 1:10 to 1:100 dilution of household bleach). Broken glass picked up mechanically, never by hand. Contaminated laundry handled with minimal agitation and bagged at location of use.
- Regulated waste: liquid or semi-liquid blood/OPIM, items that would release blood if compressed, items caked with dried blood, contaminated sharps, pathological and microbiological wastes. Placed in closable, leakproof, labeled or red color-coded containers.
- Labels: fluorescent orange or orange-red with the biohazard symbol and the word BIOHAZARD; red bags or containers may substitute.
- Hepatitis B vaccination: offered free within 10 working days of initial assignment, after training; employees may decline but must sign a declination form; may later request it at no cost. Titer testing is not required by OSHA (though CDC recommends post-vaccination testing for healthcare workers).
- Post-exposure evaluation and follow-up: confidential medical evaluation immediately after an exposure incident, documentation of route and circumstances, identification and testing of source individual where feasible and permitted by law, testing of exposed employee blood (with consent; blood sample may be held 90 days if employee declines HIV testing at the time), post-exposure prophylaxis, counseling, and a written opinion from the healthcare professional within 15 days.
- Training: at initial assignment, at least annually, and when changes occur; must be interactive with opportunity for questions; delivered by a knowledgeable person.
- Recordkeeping: medical records kept for duration of employment plus 30 years; training records kept 3 years; sharps injury log (type and brand of device, department, explanation of incident) maintained by employers required to keep OSHA 300 logs. Needlestick and sharps injuries involving contamination are OSHA recordable.

5. Other Important Regulatory and Guidance Sources

- 29 CFR 1910.134 Respiratory Protection: applies when respirators are used for bioaerosols (e.g., N95 for TB, mold remediation).
- 29 CFR 1910.132 PPE and 1910.141 Sanitation.
- General Duty Clause, Section 5(a)(1): used by OSHA for Legionella, mold, and other biological hazards without a specific standard.
- OSHA 29 CFR 1910.1200 Hazard Communication: does not directly cover biological agents (although it does cover chemical disinfectants used for control).
- CDC/NIH Biosafety in Microbiological and Biomedical Laboratories (BMBL): defines Biosafety Levels 1 through 4.
- ANSI/ASHRAE Standard 188: Legionellosis risk management for building water systems (water management programs).
- EPA guidance: Mold Remediation in Schools and Commercial Buildings; and A Brief Guide to Mold, Moisture, and Your Home.
- New York City Department of Health Guidelines on Assessment and Remediation of Fungi in Indoor Environments: widely referenced for remediation levels.
- ACGIH: publishes the book Bioaerosols: Assessment and Control; ACGIH does not set numerical TLVs for mold or most biological agents because of lack of dose-response data and the enormous variability in individual susceptibility.
- IICRC S520: Standard for Professional Mold Remediation.

6. Biosafety Levels (BSL)

Exam questions may ask you to match agents with containment levels:
- BSL-1: agents not known to cause disease in healthy adults (e.g., non-pathogenic E. coli). Standard microbiological practices, open bench work, handwashing sink.
- BSL-2: agents of moderate hazard associated with human disease (HBV, HIV, Salmonella, Staphylococcus aureus). Limited access, biohazard signs, biological safety cabinets for aerosol-generating procedures, PPE, autoclave available.
- BSL-3: indigenous or exotic agents with potential for aerosol transmission causing serious or lethal disease (Mycobacterium tuberculosis, Coxiella burnetii, West Nile virus). Controlled access, negative pressure, directional airflow, all work in biological safety cabinets, respiratory protection as needed, exhaust air not recirculated.
- BSL-4: dangerous and exotic agents with high risk of aerosol-transmitted, life-threatening disease and no available vaccine or treatment (Ebola, Marburg). Positive-pressure full-body suits or Class III cabinets, dedicated building or isolated zone, shower exit, decontamination of all materials.

Biological Safety Cabinets
- Class I: protects worker and environment, not the product; inward airflow, HEPA-filtered exhaust.
- Class II (Types A1, A2, B1, B2): protects worker, product, and environment; HEPA-filtered downflow and exhaust; the most common type in labs.
- Class III: gas-tight, glove-box design for BSL-4 work.
- A laminar flow clean bench is NOT a biosafety cabinet; it protects the product only and blows air toward the worker.

7. Mold: What It Is and How It Works

Biology basics
Molds are fungi that grow in multicellular filaments called hyphae and reproduce through microscopic spores. Spores are ubiquitous outdoors and indoors; mold becomes a problem indoors when it finds moisture and an organic food source. The three requirements for mold growth are:
1. Moisture (the controlling factor; relative humidity above about 60 percent, water activity, condensation, leaks, flooding).
2. Nutrient source (cellulose in drywall paper, wood, ceiling tiles, carpet dust, wallpaper paste, dust on any surface).
3. Suitable temperature (most grow between 40 and 100 degrees F, overlapping with human comfort ranges).

Because you cannot eliminate spores, nutrients, or comfortable temperatures from a building, moisture control is the key to mold control. This is the single most important concept for exam purposes. Mold growth can begin on wet materials within 24 to 48 hours, which is why EPA and FEMA guidance emphasizes drying water-damaged materials within 24 to 48 hours.

Common indoor molds
- Cladosporium: the most common outdoor and indoor mold; allergenic.
- Penicillium and Aspergillus: common on water-damaged materials; some species produce mycotoxins; Aspergillus fumigatus can cause invasive aspergillosis in immunocompromised persons.
- Alternaria: outdoor mold, strong allergen.
- Stachybotrys chartarum: the so-called toxic black mold; requires very wet cellulose materials and prolonged moisture; produces trichothecene mycotoxins; its presence indicates a chronic water problem. Note that many molds are black, and color does not identify species or toxicity.

Health effects of mold
- Allergic reactions (most common): sneezing, runny nose, red eyes, skin rash, allergic rhinitis.
- Asthma attacks in sensitized individuals.
- Hypersensitivity pneumonitis in susceptible persons after repeated exposure.
- Irritation of eyes, skin, nose, throat, lungs from spores and MVOCs (even in non-allergic people).
- Opportunistic infections in immunocompromised persons (aspergillosis).
- Toxic effects from mycotoxins: well documented via ingestion; inhalation effects in buildings remain scientifically debated. Exam answers should reflect that a causal link between indoor mold and severe toxic effects is not established, while allergic and irritant effects are well established.

Important: There are no federal OSHA permissible exposure limits or ACGIH TLVs for mold or mold spores. There are no established health-based numeric standards for airborne mold concentrations. This is tested frequently.

8. Mold Assessment

The assessment process follows standard industrial hygiene logic: anticipate, recognize, evaluate, control.

Step 1: Visual inspection and moisture investigation
This is the most important assessment tool. Look for visible growth, water stains, discoloration, musty odors, peeling paint, warped materials, condensation, and known leak history. Use moisture meters (pin and pinless), infrared thermography, hygrometers, and boroscopes to find hidden moisture in wall cavities, above ceilings, and under flooring. Identify and document the moisture source; remediation will fail if the source is not corrected.

Step 2: Decide whether sampling is needed
EPA guidance states that sampling is generally not necessary when visible mold is present; the response is to fix the moisture problem and remove the mold regardless of species. Sampling may be warranted to:
- Document conditions when occupants have health complaints and no visible mold is found.
- Locate hidden sources.
- Verify post-remediation clearance.
- Address litigation or insurance needs.
- Compare indoor to outdoor spore types and concentrations.

Step 3: Sampling methods (if used)
- Air sampling: spore trap (non-viable, e.g., Air-O-Cell cassettes at about 15 L/min for 5 to 10 minutes) counts total spores; viable (culturable) sampling with Andersen impactors onto agar plates identifies species but undercounts dead and non-culturable spores. Always collect outdoor comparison samples at the same time.
- Surface sampling: tape lift, swab, bulk material; confirms that visible growth is mold and identifies genus.
- Dust sampling: ERMI (Environmental Relative Moldiness Index) using DNA-based PCR; a research tool, not recommended by EPA for routine use.
- Interpretation: Indoor spore types and concentrations should be similar to or lower than outdoors. An indoor-dominant genus (especially Stachybotrys, Chaetomium, or elevated Aspergillus/Penicillium) suggests an indoor amplification source. Because there are no numerical limits, results are interpreted by comparison and by a qualified professional. Samples should be analyzed by a laboratory accredited under the AIHA Environmental Microbiology Laboratory Accreditation Program (EMLAP).

9. Mold Remediation

General principles
1. Identify and correct the moisture source first.
2. Protect workers and occupants (especially sensitive individuals: infants, elderly, asthmatics, immunocompromised).
3. Contain the work area to prevent cross-contamination.
4. Remove, not just treat, contaminated porous materials.
5. Clean non-porous and semi-porous materials.
6. Dry everything thoroughly.
7. Verify by visual inspection (and sampling if needed) that remediation is complete.

Remediation levels (EPA approach, based on area of visible growth)
- Small: under 10 square feet (about 3 feet by 3 feet). Can be done by trained building maintenance staff. PPE: N95 respirator, gloves, goggles. Containment: none required beyond basic dust control; work area unoccupied.
- Medium: 10 to 100 square feet. PPE: N95 or half-face respirator with P100 cartridges, gloves, goggles, disposable coveralls recommended. Containment: limited (cover doorways and vents with plastic sheeting, seal with tape, wet methods, dust suppression). Trained personnel; adjacent areas may need to be vacated.
- Large: over 100 square feet or when heavy contamination or HVAC contamination is suspected. PPE: full-face respirator with P100 cartridges or PAPR, disposable full-body coveralls with head and foot covers, gloves. Containment: full containment with double-layer polyethylene sheeting, decontamination chamber (airlock), negative air pressure using HEPA-filtered air scrubbers exhausted outdoors, HVAC sealed off. Work performed by experienced remediation professionals, often with an independent assessor for clearance.

NYC guideline levels (often referenced): Level I under 10 sq ft; Level II 10 to 30 sq ft; Level III 30 to 100 sq ft; Level IV over 100 sq ft; Level V for HVAC systems (under 10 sq ft vs. over 10 sq ft). Newer versions simplify to small (under 10 sq ft), medium (10 to 100 sq ft), and large (over 100 sq ft). For the exam, the 10 and 100 square foot thresholds are the key numbers.

Material-specific handling
- Porous materials (drywall, ceiling tiles, insulation, carpet, upholstered furniture, paper): generally discard if moldy or wet for more than 48 hours. Bag in sealed plastic before carrying through clean areas.
- Semi-porous materials (wood, concrete): clean by HEPA vacuuming, wire brushing, sanding, or abrasive methods, then dry.
- Non-porous materials (metal, glass, hard plastic, tile): clean with detergent and water, dry thoroughly.
- Biocides and bleach: EPA does not recommend routine use of biocides or bleach for mold remediation; dead mold is still allergenic, so physical removal is essential. If a biocide is used, ventilate and follow label directions; never mix bleach with ammonia. Antimicrobial coatings (encapsulants) may be applied only after cleaning and drying.
- HVAC: shut down during remediation; do not run a system known or suspected to be contaminated; use the NADCA ACR standard for duct cleaning; replace contaminated porous duct liner.

Worker protection in remediation
Respirators must be used in a written program under 1910.134 (medical evaluation, fit testing, training). Gloves should be selected based on the cleaning agent (e.g., natural rubber or nitrile for mild detergents; neoprene, nitrile, or PVC for stronger disinfectants). Eye protection should be non-vented goggles. Follow OSHA construction standards for demolition, ladders, electrical, and lead/asbestos when disturbing older building materials (a pre-remediation asbestos and lead survey is often required).

Post-remediation verification (clearance)
- Moisture source corrected and materials dry (moisture content verified).
- No visible mold, dust, or debris; no musty odor.
- Occupants return without health complaints.
- Optional air and surface sampling comparing to outdoor and non-affected indoor areas.

Prevention
- Fix leaks promptly; dry wet materials within 24 to 48 hours.
- Keep indoor relative humidity between 30 and 60 percent (ideally 30 to 50 percent).
- Ensure adequate ventilation and exhaust in bathrooms, kitchens, and laundry areas.
- Insulate cold surfaces to prevent condensation.
- Maintain HVAC drain pans and filters; ensure proper slope and drainage.
- Address building envelope issues and grading/drainage around foundations.

10. Legionella (A Frequently Tested Biological Hazard)

Legionella pneumophila is a bacterium that thrives in warm water (77 to 113 degrees F, optimum about 95 to 115) in stagnant conditions with biofilm, scale, and sediment. It is transmitted by inhalation of aerosolized water from cooling towers, evaporative condensers, hot water systems, showers, whirlpool spas, decorative fountains, and humidifiers; it is not spread person to person. Legionnaires disease is a severe pneumonia (2 to 10 day incubation); Pontiac fever is a milder flu-like illness. Controls: maintain hot water storage at or above 140 degrees F and delivery at or above 122 degrees F where scald risk is managed; keep cold water below 68 degrees F; eliminate dead legs; flush infrequently used outlets; biocide treatment and routine cleaning of cooling towers; drift eliminators; ASHRAE 188 water management program with a team, system description and flow diagrams, control points, monitoring, corrective actions, and verification/validation.

11. Other Workplace Biological Scenarios to Recognize

- Tuberculosis: airborne; TB skin test or IGRA blood test for surveillance; N95 or better respirators; airborne infection isolation rooms with negative pressure; OSHA enforces via General Duty Clause and respiratory protection standard.
- Histoplasmosis: disturbing accumulations of bird or bat droppings (e.g., demolition, bridge work, attics); wet methods, respirators (N95 minimum, often PAPR), disposable clothing.
- Hantavirus: rodent droppings and urine; never dry sweep or vacuum; wet with disinfectant first; use gloves and respirator.
- Anthrax: handling animal hides, wool, and the 2001 mail incidents; cutaneous, inhalation, gastrointestinal forms.
- Agricultural hazards: farmers lung (hypersensitivity pneumonitis from thermophilic actinomycetes in moldy hay), organic dust toxic syndrome, silo gas (chemical), zoonoses from livestock.
- Wastewater: Hepatitis A, E. coli, Giardia, Leptospira, endotoxins; immunizations (Hepatitis A and B, tetanus), hygiene facilities, PPE.
- Tick-borne disease: Lyme disease, Rocky Mountain spotted fever; repellents with DEET or permethrin-treated clothing, tick checks, light-colored long clothing.
- Insect stings: anaphylaxis; epinephrine auto-injector availability in first aid planning.
- Latex allergy: use powder-free, low-protein gloves or non-latex alternatives (nitrile, vinyl).
- Emergency response and flooding: contaminated floodwater (sewage, chemicals), mold, tetanus; prioritize drying, PPE, vaccinations.

12. Applying the Hierarchy of Controls to Biological Hazards

- Elimination/Substitution: remove the moisture source; replace contaminated materials; use non-latex gloves; use needleless IV systems; substitute less hazardous organisms or inactivated agents in labs.
- Engineering controls: biological safety cabinets, negative-pressure isolation rooms, local exhaust ventilation, HEPA filtration, sharps containers, self-sheathing needles, UV germicidal irradiation (upper-room UVGI), drift eliminators on cooling towers, water temperature control, dehumidification.
- Administrative controls: exposure control plans, vaccination programs (HBV, tetanus, influenza, Hepatitis A), medical surveillance, training, Universal/Standard Precautions, housekeeping schedules, restricted access, cough etiquette, hand hygiene, water management programs, limiting time in contaminated areas.
- PPE: gloves, gowns/coveralls, eye and face protection, respirators (N95 minimum for bioaerosols; surgical masks are not respirators and do not protect against airborne agents).

Remember that handwashing is the single most effective practice to prevent transmission of infectious agents, and that PPE is the last line of defense.

13. Exam Tips: Answering Questions on Biological Hazards and Mold

Tip 1: Moisture is always the root cause of mold. If a question asks for the first step, most important step, or best long-term control for a mold problem, the answer involves finding and fixing the water or humidity source. Removing mold without fixing moisture is a wrong answer. Keep relative humidity below 60 percent (ideally 30 to 50 percent) and dry wet materials within 24 to 48 hours.

Tip 2: Know that there are no numerical exposure limits for mold. Any answer choice citing an OSHA PEL, ACGIH TLV, or a specific spore count threshold for mold is incorrect. Interpretation relies on indoor-versus-outdoor comparison and a qualified professional.

Tip 3: Sampling is usually not the first step. EPA guidance says visible mold does not need to be sampled to be remediated. If a scenario describes visible growth and asks the best action, choose remediation and moisture correction over species identification. Sampling is appropriate when the source is hidden, for clearance, or for documentation.

Tip 4: Memorize the 10 and 100 square foot thresholds. Under 10 sq ft = small, trained maintenance staff, N95, gloves, goggles, minimal containment. 10 to 100 sq ft = medium, limited containment, N95 or half-face with P100. Over 100 sq ft = large, full containment, negative pressure with HEPA exhaust, full-face respirator or PAPR, full-body disposable coveralls, professional remediators.

Tip 5: Porous materials are discarded; non-porous materials are cleaned. Moldy drywall, ceiling tiles, insulation, and carpet are removed and bagged. Metal, glass, and tile are cleaned with detergent and dried. Wood and concrete may be cleaned by HEPA vacuuming and abrasive methods.

Tip 6: Bleach and biocides are not the answer. EPA does not recommend routine biocide use; dead mold is still allergenic; physical removal plus drying is the standard. Never choose fogging or spraying as a substitute for removal.

Tip 7: Treat the Bloodborne Pathogens Standard numbers as must-know facts. HBV vaccine within 10 working days; declination form in writing; ECP reviewed annually; post-exposure written opinion within 15 days; medical records duration of employment plus 30 years; training records 3 years; training at initial assignment and annually; sharps injury log required; blood sample held 90 days if HIV testing declined; bleach dilution 1:10 to 1:100; labels fluorescent orange or orange-red; no recapping or bending needles.

Tip 8: Distinguish Universal Precautions from Standard Precautions. Universal Precautions (OSHA term) treat all blood and OPIM as infectious. Standard Precautions (CDC term) extend this to all body fluids, secretions, and excretions except sweat. Also know that feces, urine, sweat, tears, saliva (except in dental work), nasal secretions, and vomitus are NOT OPIM unless visibly bloody.

Tip 9: Match the route of exposure to the control. Airborne agents (TB, mold, Legionella, histoplasmosis) require respiratory protection and ventilation controls; surgical masks are not respirators. Bloodborne agents require sharps controls, gloves, and vaccination. Ingestion hazards require hygiene, handwashing, and prohibiting eating and drinking in work areas.

Tip 10: Legionella is inhaled from water aerosols, not swallowed and not spread person to person. Questions mentioning cooling towers, hot water tanks, showers, or decorative fountains with pneumonia cases point to Legionella. Controls are temperature management, eliminating stagnation, biocides, cleaning, and an ASHRAE 188 water management program.

Tip 11: Know biosafety level agent examples. BSL-1 non-pathogenic E. coli; BSL-2 HBV, HIV, Salmonella; BSL-3 TB, Coxiella, West Nile; BSL-4 Ebola, Marburg. Class II biosafety cabinets protect worker, product, and environment; a clean bench protects only the product.

Tip 12: Apply the hierarchy of controls. When multiple control options appear, rank elimination and engineering controls above administrative and PPE unless the question specifically asks what the worker should wear. The best control for sharps injuries is an engineering control (safer device) rather than training or gloves.

Tip 13: Read for the qualifying words. Terms like first, most important, best, minimum, and required change the correct answer. A question asking for the minimum respirator for small mold cleanup wants N95; a question asking for the appropriate respirator for large-scale remediation wants full-face with P100 or PAPR.

Tip 14: Recognize hypersensitivity and toxic syndromes by setting. Farmers lung = moldy hay = hypersensitivity pneumonitis. Organic dust toxic syndrome = heavy grain/compost dust = endotoxin. Humidifier fever = contaminated humidifiers. Byssinosis = cotton dust (endotoxin contribution). Histoplasmosis = bird/bat droppings. Hantavirus = rodent droppings. Psittacosis = birds. Q fever/brucellosis = livestock.

Tip 15: Beware of color-based mold myths. Black mold is not necessarily Stachybotrys, and not all Stachybotrys is black. Species cannot be identified visually; only laboratory analysis identifies genus or species. All visible mold should be remediated regardless of type.

Tip 16: Separate established from unproven effects. Allergic, asthma, and irritant effects of indoor mold are well established; invasive infections affect primarily the immunocompromised; inhalation mycotoxicosis in buildings is not scientifically established. Choose answers reflecting this consensus.

Tip 17: Remember the OSHA recordability angle. A needlestick or sharps injury contaminated with blood or OPIM is automatically recordable on the OSHA 300 log (with privacy case treatment). A splash exposure is recordable only if it results in a diagnosed bloodborne illness or meets other recording criteria.

Tip 18: Think like an industrial hygienist. Anticipate the hazard from the job description, recognize it through inspection and history, evaluate with qualitative and (when justified) quantitative methods, and control with the hierarchy. Exam scenarios that describe occupant complaints, musty odors, and water intrusion are asking you to apply this systematic process, not to jump to air sampling or to chemical treatment.

14. Quick Review Summary

- Biological hazards: bacteria, viruses, fungi, parasites, prions, endotoxins, mycotoxins, allergens, vectors.
- Routes: inhalation, ingestion, dermal/mucous membrane, injection. Chain of infection has six links; break any one.
- 29 CFR 1910.1030: ECP annual review, Universal Precautions, engineering and work practice controls, HBV vaccine within 10 days, post-exposure follow-up with written opinion within 15 days, labeling, regulated waste, training annually, records 30 years after employment.
- Mold needs moisture, nutrients, and temperature; control moisture. Growth starts in 24 to 48 hours. RH below 60 percent.
- No PELs or TLVs for mold; sampling optional; compare indoor to outdoor; use EMLAP-accredited labs.
- Remediation levels: under 10 sq ft small; 10 to 100 medium; over 100 large with full containment and negative pressure.
- Discard porous materials; clean non-porous; do not rely on bleach or biocides; dead mold still causes allergy.
- Legionella: warm stagnant water, inhaled aerosols, cooling towers and hot water systems, ASHRAE 188.
- BSL-1 through BSL-4; Class I, II, III biosafety cabinets.
- Hierarchy of controls applies; handwashing is the most effective single practice; PPE is last.

Master these principles and you will be well prepared for any biological hazard or mold question on the ASP exam, and more importantly, you will be able to protect workers from some of the most under-recognized hazards in the modern workplace.