Industrial Hygiene Exam 2

Types of biological hazards

• Bloodborne pathogens

• Bacteria

• Viruses

• Fungi

• Plants

• Animals

Living organisms and organic toxins

Infectious agents, allergens, and toxic metabolic byproducts capable of impairing human physiological functions

Dynamic Replication

Biological agents can replicate inside a host, or other medium under favorable conditions

Dose-Response ambiguity

Infectious doeses vary by immune status and single particles can cause illnesses, classic threshold limits are difficult to construct

Broad Clinical Outcomes

Health impacts can range from acute infections to chronic hypersensitivities liek asthma and toxicosis

Bacteria and endotoxins

single celled prokaryotes that cause pulmonary and systemic infections

Viruses and bloodborne agents

Submicroscopic parasites that require host cells to replicate and transmit

Fungi and mycotoxins

Eukaryotic organisms that produce spores causing allergic responses and pulmonary disease

High risk occupational settings

• healthcare and clinics

• Agriculture and grain silos

• Wastewater operations

• Biomedical labs

Percutaneous injuries

accidental punctures with contaminated needles that cause bloodborne pathogens in clinical personnel

Mucociliary Splashes

Blood, secrections, or wastewater, that directly contact your skin and overcome epidermal barrier defenses

Vector-Borne Inoculation

Outdoor workers that face tick and misquito vectors that carry lyme disease and arbovirus

Droplet nuclei inhalation

Drpolets that stay suspended for hours in ventillation systems

Fomite-Mediated Ingestion

Inadequate break hygiene allows the transfer of pathogens from contaminated gloves to food or mouth

Mucosal Adhesion

Highly persistent pathogens that can maintain infectivity across shifts

Zoonotic diseases

• Rabies

• Lyme Disease

• Hantavirus

• Prions

• Parasites

• HIV

• Hepatitus

How many specific OSHA numerical PELs

0

“Single Hit Model”

Every single individual pathogen molecule or organism has a non-zero chance of surviving host defeses and multiplying to trigger adverse health outcomes

OPIM

Other Potentially Infectious Materials

Bloodborne pathogen risks of exposure

• Direct contact

• Indirect contact

• Respiratory transmission

• Vector transmission

Universal/standard safety precautions

• PPE

• Sharps safety and disposal

• Hygiene and cleaning

Risk Group 1

Agents are not associated with disease in healthy humans, and represent little to no risk to an individual or the community

Risk Group 2

Agents associated with disease are rearely serious and interventions are often availible. Moderate risk to individual, low risk to the community

Risk Group 3

Agents are associated with serious or lethal disease, and treatment may be availible, high risk to an individual, low risk to a community

Risk Group 4

Agents are likely to cause serious or lethal disease, where treatement are not usually availible, poses high risk to individuals and community

What group uses Risk groups

NIH

What organizations use biosafety levels

(CDC/NIOSH)

Controls for biological hazards

• Engineering and work practice controls

• Standard precautions

• Written exposure control plan (ECP)

• PPE

Current bacteria challenges

• E.coli

• Salmonella

• Staphylococcus

• MRSA

Current Virus challenges

• Influenza

• HIV

• MPOX

• Hepatitus

• COVID

Current fungi challenges

• Aspergillus

• Candida

• Molds

Bioterrorism threats

• Anthrax

• Ricin

HHE

NIOSH Health Hazard Evaluation Program

NIOSH Health Hazard Evaluation Program key points

• Free service that evaluates workplace hazards

• Employers and employees can request if they suspect that hazards are harming employee health

• Reccomend ways to reduce hazards

Authority and scope

• Mandates responsive wrokplace investigations

• focuses on science instead of punitive citations

Core categories evaluated

• Chemical hazards

• Physical hazards

• Biological hazards

• Ergonomic hazards

• Psychosocial hazards

NIOSH HHE vs OSHA inspection

• NIOSH identifies hazards, OSHA verifies safety compliance

• NIOSH is non punitive, OSHA has regulatory authority

• NIOSH makes reccomendations without fines, OSHA has enforceable citations, fines, and abatement dates

What was the result of the HHE of LeConte Hall

Based on a lack of evidence of significant exposure to chemical and physical hazards, it is unlikely that cancer can be attributed to the environment

Evaluation of exposure to metals and noise during shipbuilding and repair operations

• NIOSH measured employee exposure to airborne metals and noise

• Some employee manganese exposure were above RELs

• Some employee noise exposure was above RELs

Evaluation of a Blastomycosis outbreak at a pulp and paper mill

• NIOSH held informational sessions for employees to ask questions

• Conducted indoor and outdoor sampling

• Tested ventillation systems

• Conducted screenings, questionairres, and tests

• 162/645 workers had blastomycosis

• Exposure to pooling water and visible mold were sources

• Environmental sampling did not identify blastomyces

Steps in HHE

1. Hazard Identification

2. Exposure Assessment

3. Risk Characterization

4. Implementation of control measures

Hazard Identification

• Recognize substances or activities that can cause harm

• Workplace tour

• Review SDS

• Employee interviews

• Record analysis

• Consult regulatory guidelines

Exposure assessment

• Determine extent of exposure to hazard

• Air and surface sampling

• Medical monitoring

• Observing work practices and durations

Risk characterization

• Combine hazard and exposure information to estimate risk

• Risk = Hazard x Probability

• Qualitative: descriptive analysis

• Quantitative: numerical estimations using models and data

Interventions for control

• Elimination

• Substitution

• Engineering controls

• Administrative controls

• PPE

Electronics recycling case study, what NIOSH did

• Evaluated the facility

• Collected surface, handwipe, and air samples for 32 elements and 22 flame retardants

• Collcted blood samples for heavy metals and flame retardants

• Collected urine samples fro flame retardants

• Measured sound pressure levels

• Observed employees to assess ergonomical hazards

Electronics case study key findings

• Found levels of flame retardants on employees hands increased after work

• Found 22 flame retardants in the air

• No personnel metal exposure above limits

• Found some flame retardants and metals in blood and urine

• Found lead and cadmium in employee blood

Electronics case study key findings part 2

• Employees wear earplugs and respirators incorrectly

• Workstations were unadjustable and couldn’t match the height of their operator

• Anti-fatigue mats were availible but rarely used

• Poor lighting

• Dry sweeping

Electronic recycling employer options

• Involve employees in a lead exposure prevention program

• Provide employees with a lead removing product to wash their hands

• Retrain employees on proper use of PPE

• Replace antifatigue mats

• Provide adjustable workstations

Electronics recycling case study, employee responsibility

• Wash hands with lead removing product

• Do not dry sweep, use wet cleaning methods

• Wear ear plugs and respirators correctly

• Use anti fatuque mats and workstation lights

Health Hazard Evaluation is

Critical for worker safety

HHE invovles sytematic steps

• Identification

• Assessment

• Characterization

• Control

Effective controls rely on

The heirarchy of controls

Essesntials of HHE

Continuos monitoring, and reevaluation

Types of PPE

1. Respiratory protection

2. Eye and Face protection

3. Head protection

4. Foot and leg protection

5. Hand and arm protection

6. Body protection

7. Hearing protection

PPE program components

1. hazard assessment

2. PPE selection

3. Develop Standard Operating procedures

4. Fit PPE to the worker

5. Training

6. Maintenance and storage of PPE

7. Record Keeping

8. Program evaluation

PPE training

• When is it neccessary

• What kind is neccessary

• Proper useage

• Limitations of equipment

• Proper care and disposal

PPE level D

• “Dirty work”

• Work atmosphere has no known hazard

• Equipment depends on the situation

PPE level C

• Contaminants will not adersely affect or be absorbed through exposed skin

• C is for cartridge, full face or half face APR

APR

Air Purifying Respirator

SCBA

Self Contained Breathing Apparatus

PPE level B

• Non gas tight encapsulating suit

• Can be worn in IDLH situations if contaminants cannot be absorbed or are not hazardous to skin

• Highest respiratory protection when less skin/eye protection is needed

• B is for breathing air, supplied by SCBA

PPE level A

• Most protective level “Moon suit”

• Same respiratory protection as level B

• Gloves inner and outer chemical resistant

• Chemical resistant boots

PPE limitations

• Heat stress (level A only worn for 30 min)

• Restricted movement

• Physiological and psychological stress

Limitations of chemical prtective equipment

• Not ideal, last line of defense

• Won’t remain impervious forever

• Not resistant to all chemicals

• Permeation times can vary

Permeation

Rate a chemical will move through intact material

Breakthrough time

The time it takes to permeate completely through a material

Degredation

Deterioration of material due to chemical contact (Stiff, brittle, swell, dissolve)

Respirators are the _______ means of exposure control

Least satisfactory

When is respiratory protection required

• When there are airborne hazards

• Emergenices

• Lack of oxygen

• Firefighting

Types of respiratory fits

• Tight fitting

• Loose fitting

Classes of respirators

• Air purifying

• Atmosphere supplying

SAR vs APR

• APR relies on ambient air

• SAR supplies its own

Only 2 types of respirators can be used in IDLH conditions

1. Full facepiece

2. Combination facepiece

APF

Assigned Protection Factor. Reduces the environmental concentration of the hazard by the factor of it’s number

PAPR

Powered Air Purifying Respirator

APF numbers

5, 10, 25, 50, 1000

How to calculate APF

Divide air concentration by PEL, and round up to nearest APF number

(30 ppm ÷5 ppm PEL) = 6.

The minimum APF would be 10

MUC

Maximum Use Concentration

Maximum Use Concentration

The maximum atmospheric concentration of a substance that an employee can be expected to be protected from when wearing a respirator

How to calculate MUC (Maximum Use Concentration)

Multiply the APF (Assigned Protection factor) of the respirator by the PEL, STEL, or C

Respiratory Protection Program

• WRITTEN worksite specific procedures

• Fit testing

• Medical evaluations

Fit testing

Qualitative (Pass/fail)

• Bitrex (used in lab)

Quanittative (Numerical)

OSHA 2025 most cited standards

#9 PPE = 1,956 violations

#5 Respiratory protection = 2,294 violations

Industrial Hygiene definition

• Anticipation

• Recognition

• Evaluation

• Control

Anticipation

Predicting potential hazards before processes begin

Recognition

Identifying existing health hazards

Evaluation

Quantifying exposure levels

Control

Implementing engineering and administrative safeguards

Hippocrates

Father of medicine, first to link occupational environment to symptoms

Pliny the Elder

Gave miners animal bladders to cover mouths

Bernardino Ramazzini

Father of OCCUPATIONAL medicine

Birth of industrial hygiene

1913-1914

Triangle shirtwaist fire

Industrial garment factory fire

when was the term industrial hygiene first used

1920

Hawk’s nest disaster

Silica dust in mine collapse caused silicosis

Texas City Disaster

Ammonium nitrate fertilizer explosion

Minamata disaster

methylmercury discharge

Bhopal

gas tragedy, methyl isocyanate leak

Deepwater horizon

Oil rig fire