OHS 421 - Chapter 1

Occupational hygiene: 4 principles. Types of occupational health hazards. Reasons for air sampling a.k.a hygiene measurements, exposure assessments

What are the 4 principles of occupational hygiene?

Anticipation, Recognition, Evaluation, Control

Anticipation

Aware of issues in the workplace before they arise

Recognition

Identifying potential hazards/risks that already exist

Evaluation

The process of assessing the extent and severity of identified hazards and risks.

Control

Measures that ideally eliminate or reduce hazards and risks.

Controls can be implemented at the…

(i) Source (ii) Pathway (iii) Worker (iv) Combo of all

Name the hierarchy of controls

Elimination, Substitution, Engineering controls, Administrative controls, and Personal Protective Equipment.

Elimination

Physically remove the hazard

Substitution

Replace the hazard with a less dangerous one.

Engineering Controls

Isolate workers from the hazard at its source

Administrative Controls

Policies and procedures that change the way people work

Personal Protective Equipment

Equipment worn to minimize exposure to hazards. The last line of defence.

Which controls are NOT practical?

Elimination and substitution

What are the 3 major hazards in OHS?

Chemical, Biological, Physical

Chemical Hazards…

are substances that can cause harm due to their chemical state, including how and where it’ll travel, how they enter and interact with the body. Route of entry: Inhalation, Absorption, Ingestion, or combo of all

Biological Hazards…

are living organisms or their byproducts that can cause harm to human health, including bacteria, viruses, mold. Route of entry: Inhalation, Absorption, Ingestion, Injection, or combo of all

Physical Agents…

are energy sources that can cause harm, including noise, radiation, extreme temperatures, and vibration.

Why is air sampling done?

To identify the type of airborne hazard chemical

To determine whether the exposure complies with legislated limits

To relate health effects with potential exposure

To determine the effectiveness of controls to reduce the airborne chemical concentration

To obtain exposure information for health research or epidemiological studies

What is an occupational exposure limit (OEL)?

Occupational exposure limits represent an acceptable level of risk with respect to chemical hazards

What are the three types of OEL categories?

1) Time-weighted average (TWA)

2) Short term exposure limit (STEL)

3) Ceiling limit (C or CEL)

Time-weighted average (TWA)…

Time-weighted average concentration for a normal 8-hr workday and 40-hr workweek to which nearly all workers may be repeatedly exposed on a daily basis without adverse effect

Short term exposure limit (STEL)

15-minute time-weighted average exposure which should not be exceeded at any time during the workday, even if the 8-hour TWA is within the TLV-TWA

Ceiling limit (C or CEL)

Maximum concentration that should never be exceeded

Threshold Limit Value (TLV)

Exposure limits published by the American Conference of Governmental Industrial Hygienists (ACGIH). Also used by Ontario govt

What law are employers required to follow in regards to limiting chemical hazards?

Section 4, Reg 833, Control of Exposure to Biological or Chemical Agents, to limit the exposure to hazardous agents in accordance with the values set out in Table 1