Industrial Hygiene Exam 1

Industrial Hygiene Definition

Anticipation, Recognition, Evaluation, and Control of environmental factors in the workplace

Pliny the Elder

Created the first known respirators for miners

Agricola & De Re Metallica

First study detailing the hazards for miners

Routes of occupational exposure

Inhalation, Ingestion, Injection, and Dermal Injection

Toxicokinetics: ADME

Absorption, Distribution, Metabolism, Excretion

Absorption

The process by which a toxin crosses biological membranes, into your bloodstream

Distribution

Translocation of toxins, through bodily tissues, target organs, or storage sites

Metabolism

Biotransformation (primarily in the liver) that converts toxicants into hydrophilic metabolites for detoxification

Excretion

Elimination from the body via, urine, exhalation, or feces

Acute exposure

High concentration exposure over a brief period

Chronic exposure

Low level exposure over an extended duration

Local toxicity

Adverse effects at the point of direct contact (skin acid burn, upper airway irritation)

Systemic toxicity

Toxin is absorbed into the bloodstream and moves to a target organ

Safety Data Sheet (SDS)

Key toxicological data, exposure symptoms, regulatory benchmarks

TLV

Threshold Limit Value

PEL

Permissible Exposure Limit

REL

Reccomended Exposure Limit

True Gases

Substances that exist naturally in the gaseous state

Vapors

The gases of a substance that typically exist as a liquid or solid

Hazard =

Toxicity + exposure potential

Solvent toxicity mechanisms

Dermal and respiratory pathways, because of easy penetration of biological membranes

CNS depression

Dissolves neural membranes

Dermal hazards

Removes protective skin lipids, leading to contact issues, and enhanced secordary exposure

Simple asphyxiants

gases that drop oxygen levels below 19.2%, leading to hypoxia without chemical toxicity

Chemical asphyxiants

Prevent cellular respiration, even when oxygen levels are normal

LEL

Lower Explosive Limit

UEL

Upper Explosive Limit

Air sampling methodologies

Solid sorbent tubes, Direct readings, Colorimetric tubes

Solid Sorbent Tubes

Active air sampling using carbon, or silica gel tubes, driven by personal sampling pumps

Colorimetric tubes

Stain detector tubes, for rapid spot check measurements of specific toxic gases

Concentration (ppm) =

Concentration (mg/m3) x 24.45 / Molecular weight (g/mol)

Controlling vapors and gases

Substitution, Ventillation, Administration, Respirators / PPE

Substitution

Replacing high hazard substances with low volatility alternatives

Ventillation

Install Local Exhause Ventillation points at the source (LEV), and ensure explosion proof electrical fittings

Administration

Implement rotation schedules, worker communication, SDS, solvent storage limits, and air monitoring protocols

Respirators / PPE

Use NIOSH approved Organic Vapor (OV) cartridges, and chemical resistant gloves

Aerosol

Solid or liquid particles suspended in a gaseous medium

Dusts and Fumes

Dust: Solid mechanically generated particles. Fumes: Solid condensation particles from molten metal

Mists and Smoke

Mist: Liquid droplets formed by spraying or condensation. Smoke: Liquid or solid particles resulting from incomplete combustion

Fibers

Solid elongated particles with an aspect ration greater than 3:1 (asbestos)

Bioaerosols

Airborne biological agents including bacteria, fungal spores, pollen, and viral capsids

Aerodynamic Effective Diameter

Shows airborne residence time, inertial impaction, and depth of penetration into the human respiratory system

Inertial impaction

Large particles collide with airway bends in the nasopharyngeal and upper bronchial tube

Gravitational settling

Intermediate particles settle in smaller tracheobronchial airways via gravity

Brownian diffusion

Ultrafine particles move randomly contacting alveolar membranes

Aerosol quantification metrics

Mass Concentration, Number Concentration, Fiber Count Metric, Surface Area Dose

Health effects of particulates

Pneumoconiosis, Fibrosis, Systemic toxicity, and Carcinogenicity

Pneumoconiosis and fibrosis

Accumulation of particles in deep alveolar tissue, leading to irreversable scarring and lung rigidity

Occupational bioaerosols

Endotoxins, Fungal spores, agricultural dusts, airborne pathogens

Occupation controls and methods

Dorr-Oliver/ Nylon Cyclones, Local Exhaust Ventillation (LEV), HEPA filtration, Wet Suppression

Purpose of lab reports

Communicate results, provide data for compliance, document methodology and results, and support decisions

1. Cover page

Project name, company name, date, prepared by, and contact information

2. Executive summary

• Brief overview of why sampling was conducted

• key findings

• overall compliance status

• High level recommendations

3. Introduction/ Objectives

• Purpose of the survey

• Description of workplace processes and potential hazards

• applicable regulations

4. Methods

• sampling device type

• calibration details

• duration of sampling

• location/conditions

• method reference (NIOSH, OSHA)

5. Results

• Raw results

• Calculated concentrations

• Tabular format (Sample ID | Location/Task |

  Duration | Result | PEL/REL/TLV | Compliance

  Status)

• Graphs/figures

6. Discussion

• Compare results with regulatory exposure limits

• Identify operations with the highest exposure

• Highlight areas of concern

• Assess potential health risks

• Limitations of the study

7. Conclusion

• Compliance determination

• Suggested controls

• Need for further sampling and monitoring

8. Apendices

• logs

• photos

• certifications

• notes

• diagrams

Core components for air sampling

Why (Introduction), How (Methods), What (Results), What it means (Discussion), What to do about it (Conclusion)

Most cited air contaminants

SiO2, Asbestos, Lead, Hexavalent Chromium, Benzene, Formaldehyde, Carbon Monoxide

OEL

Occupational Exposure Limit

OSHA

Occupational safety and Health Association

OSHA Mission

To save lives, prevent injuries, and protect the health of America/s workers

People outside of OSHA

• Self employed

• Mine workers

• Public employees

Employer responsibilities

Provide a workplace free form recognized hazards

Costs

• Accident costs

• Direct Costs

• Indirect costs

Heirarchy of controls from least to most effective

PPE, Administrative controls, Engineering controls, Substitution, Elimination

Risk Calculation

Probability x severity

Exposure Assessment Primary Goal

Determine acceptability of exposures to all workers on all days

What must be done before moving to the next step

Define what is acceptable

Compliance based assessment primary goal

Complying with established or voluntary OELs

Limitations of Compliance Based Assessment

• does not account for variation in exposure levels

• Does not account for exposures without establishes OELs

Types of assessments

• Comprehensive exposure assessment

• Compliance Assessment

Questions you want during the basic characterization step (before sampling)

• What are the chemicals/agents present, and in what quantity

• Health effects from exessive exposure to the agents

• Occupational exposure Limits (OEL) for each hazard

• How is the workforce organized

• Significant sources of exposure and how the workers interact with them

• What controls are in place, how are they used and how effective are they

Heirarchy of OELs

• Quantitative Health-based OELs: Ideal from a pure toxicology standpoint

• Traditional OELs (TLVs, RELs, PELs): Technically and economically feasible

PEL

Permissible Exposure Limit

REL

Reccomended Exposure Limit

TWA

Time Weighted Average

SEG

Similar Exposure Group

SEG Exposure Category 0

<1% of OEL, No action needed

SEG Exposure Category 1

<10% of OEL, General hazard communication, procedures, and training

SEG Exposure Category 2

10-50% of OEL, Chemical specific hazard communication, and periodic monitoring

SEG Exposure Category 3

50-100% of OEL, Required monitoring, workplace inspections, medical surveillance, and biological monitoring

SEG Exposure Category 4+

>100% of OEL, Multiple levels, Implement the heirarchy of controls, and monitoring to validate respirator protection

OSHA PELs

• Legally enforceable, but scientifically outdated

• No major changes since 1970

• “Minimum wage” of exposure

• Located in 29 CFR 1910 Subpart Z

Action Level

A concentration for a specific substance calculated as an 8-hour TWA, which initiates certain required activities, such as exposure monitoring and medical surveillance

Action Level =

½ (PEL-TWA)

STEL

Short Term Exposure Limit

CL

Ceiling Limit

Short Term Exposure Limit

15 minute TWA exposure limit

Ceiling Limit

Concentration not to be exceeded at any time

IDLH

Immediately Dangerous to life or Health, based on 30 minute window for self rescue or respirator application

Biggest Indoor Air Quality concerns

Volatile Organic Compounds (VOCs), Carbon Monoxide (CO), Carbon Dioxide (CO2), and Particulate Matter (PM)

Sources of VOCs

• Building materials

• Cleaning agents

• Office equipment

• Paints

• Adhesives

Common VOCs

• Formaldehyde

• Benzene

• Toluene

Biological contaminants

• Bacteria

• Viruses

• Mold

• Fungi

Sick Building Syndrome (SBS)

When residents experience acute health symptoms associated with time spent in the building, but no specific illness or cause can be found, symptoms disappear shortly after leaving the building

SBS

Sick Building Syndrome

Cause of SBS

Unidentified