Demystifying Occupational Hygiene

Written by Abimbola Badejo, Staff Writer

At the recent Partners in Prevention 2019 Health and Safety Conference, Ontario, Canada; organized by Workplace Safety and Prevention Services (WSPS) Ontario, Canada, Dave Gardner of Pinchin Ltd. delivered a presentation on Demystifying Occupational Hygiene. Mr. Gardner is Senior Occupational Hygiene and Safety Consultant with Pinchin Ltd. Below is a summary of his presentation.

WHAT IS OCCUPATIONAL HYGIENE?

Occupational hygiene has been
defined by the United States Department of Labour Occupational Safety and
Health Administration as “that science
and art devoted to the anticipation, recognition, evaluation, and control of
those environmental factors or stresses arising in or from the workplace, which
may cause sickness, impaired health and well-being, or significant discomfort
among workers or among the citizens of the community.
1.   Simply
put, the goal of Occupational hygiene is to ensure the safety and protection of
a worker at his or her workplace, provided the worker follows a set of
guidelines  that have been put in place
to safeguard his/her health and safety.  

Typical occupational hygiene
principles include written standards, procedures and practices; workers
training as part of a knowledge management program; logical thinking on the
part of the creator; a combination of actions with words learned from the
written standards; and total compliance with associated regulations.

WHY IS OCCUPATIONAL HYGIENE PROGRAM
IMPORTANT?

An Occupational Hygiene
program is of great importance as its negligence leads to occupational injuries
and diseases. Occupational diseases are considered more significant due to
factors associated with it; which include

  • Diseases
    caused by exposure to either chemical, physical or biological agents at the
    workplace
  • Sources
    such as exposure to airborne asbestos particles, confined spaces, noise,
    construction projects, etc.
  • Categories
    namely Long Latency Illness, Noise Induced Hearing Loss (NIHL), Chronic
    Exposure and effects and Acute Exposure and effects
  • Observable
    effects which are not seen until after a long duration of exposure
  •  75% of fatalities in diseases, attributed to
    occupational origins

The Ontario Workplace Safety
and Insurance Board (WSIB) reported that approximately 130 thousand claims were
filed, and about $940 million benefit costs were released, between 2008 and
2017. Occupational diseases with long latency are mostly serious and these
account for only three percent of the occupational diseases with benefits.

Based on these factors (and
those not mentioned), reviews have been made by the Human Resources and Skills
Development Canada (HRSDC) and Labour Canada. These reviews include updates
made to the Occupational Exposure Limits (OEL) of chemicals, training workers
on the safe usage of materials and the equipment at the workplace, thorough
knowledge of the materials and substances used at the workplace, compulsory and
proper use of Personal Protective Equipment (PPE), alertness of workers to the
state of their own health and compulsory medical check-ups in relation to
workplace risk assessment.

CASE FOCUS: SUMMARY OF RISKS AND SURVEYS REPORTED FOR
WORKERS IN THE CONSTRUCTION INDUSTRY

A survey made by the Center
for Construction Research and Training regarding occupational diseases in the
construction industry reported that the workers in this industry are:

  • twice
    as likely to have chronic obstructive lung diseases, five times more likely to
    have lung cancer, thirty-three times more likely to have asbestosis
  • inclined
    to suffer a 50% increase in Lung Cancer related deaths
  • predisposed
    to noise induced hearing loss (NIHL) (50% of workers)
  • susceptible
    to elevated levels of lead in their blood (17% of workers)
  • exposed
    to the allowable 8-hour exposure limit for Manganese during welding processes.
    This was observed with workers involved in boiler making (75%), iron-working
    (15%) and pipe-fitting (7%)).

In addition, a nationwide report has disclosed that 40% of WSIB
costs are for construction occupational diseases, more construction workers die
from a combination of occupational diseases and traumatic injuries and that 2
to 6 construction workers are more likely to develop occupational lung disease
and NIHL.

As observed, most of the occupationally related diseases can
be prevented by simple tasks such as hand-washing, proper use of PPE and
correct compliance to defined regulations.

LEGISLATIONS
GOVERNING OCCUPATIONAL HYGIENE

To ensure the protection of workers in various Canadian
industries, regulations and guidelines have been put in place; some of which
require compliance by either the employee or the employer. The legislations and
related codes/standards guiding occupational hygiene in workplaces include:

Some of the provided
regulations and guidelines are specific while others are general in application.
The key to correct interpretation is to apply the correct regulation to the
right workplace situation.

An example of a proper
legislation application: Silica is
an inert substance and an irreplaceable material in most products and buildings
in the world today.  As the second most
abundant mineral on the planet, silica is used in numerous ways. Getting the
substance to the usable state requires processing, which exposes the worker to
the respirable crystalline form. The regulation (O. Reg 490/09), listing silica
as a designated substance, does not apply to the silica infused products but to
the respirable fractions which the processing worker is exposed to. The
regulation specifies an occupational exposure limit (OEL) for respirable
crystalline silica as 0.05 mg/m3 of air (cristobalite silica) and
0.1 mg/m3 of air (quartz and tripoli silica) for an 8-hour/day or
40-hour weekly exposure. This regulation, however, does not apply to the
employer or some other workers on a construction  project; but the employer’s responsibility
will be to protect the worker’s health in compliance to section 25 (2)(h) of
the OHSA, requiring employers to take every reasonable precaution in the
circumstances to protect a worker.

FUNDAMENTALS OF OCCUPATIONAL HYGIENE

Before initiating an
occupational hygiene program, a clearer understanding of basic terms is ideal.

Industrial
Hygiene
: this
is an exercise devoted to the anticipation, recognition, evaluation, and
control of those environmental stresses arising from the workplace, which may
cause the impairment of a worker’s health.

Toxicology: the study of how chemical,
physical and biological agents adversely affect biological systems. The adverse
effects include irritation, sensitization, organ failure, diseases or cancer.

Disease,
dose and exposure
:
Disease / response is caused by an agent dosage. Dosage is measured in relation
to the exposure of the worker to an agent. Mathematically, exposure is
calculated as the agent concentration multiplied by duration of exposure
(concentration x time). Therefore, sampling surveys are simply estimating the
exposure of the worker to a specific concentration of the agent. Exposure routes
may be through inhalation, ingestion, contact or skin absorption.

Threshold
Limit Values (TLV)
:
TLVs are general concentration limit values for specific chemicals, to which a
healthy adult worker can be exposed. 
However, TLVs does not adequately protect all workers as their
susceptibility levels to various chemicals are unique to them. TLVs are used by
regulators as guidelines or recommendations to assist in the control of
potential workplace hazards.

Time-Weighted
Average (TLV-TWA)
:
TWA concentration for a conventional 8-hour/day or 40-hour/week , to which a
worker may be repeatedly exposed.

Short-Term
Exposure Limit (TLV-STEL)
:
This is a 15-minute TWA exposure that should not be exceeded.

Ceiling
(TLV-C)
: This
is a concentration that must not be exceeded during any part of working
exposure

Air
Monitoring
:
This is a process of sampling the air in the workplace, on a regular basis. The
monitoring  may be qualitative (risk
assessments, hygiene walkthroughs and training) or quantitative (air, noise and
wipe sampling) in perspective.

RISK ASSESSMENT

The first focus of an
occupational hygiene program is to conduct a risk assessment of the workplace
processes.  A risk assessment shows that
20% of the activities or tasks  carried
out, leads to 80% of  risks. Carrying out
a risk assessment, focuses on the adverse effects of  a hazardous agent and the associated level of
risk if a worker is exposed to it. Approaches to risk assessment include
Critical Tasks Analysis (where stepwise task and risk inventories are made with
the focus on worker’s safety), Process Safety (where the focus is on the
process, controlling the risk to keep the worker safe) or a combination of both
approaches. Risk assessment, therefore, is done 
as thus:

  1. Making a list of the agents
    the worker is exposed to,
  2. Identifying the routes of
    entry,
  3. Identifying a relative risk
    level (low, medium or high),
  4. Documenting the control in
    place and its effectiveness.

Table 1. Requirements of a
Hazard Reviewer. Scores are used to dictate the skill level required to assess
and develop control strategies.

Risk
Score
Risk
Level
Minimum Requirements
<10 Low to Medium low Any trained employee
>10 to <20 Medium Health and Safety Department
or a contracted Health and Safety Consultant
20 & above High Certified Health and Safety Professional or Industrial Hygienist (CRSP, CSP, CIH, ROH)

DEVELOPING AIR SAMPLING
STRATEGIES

A preliminary survey is
initially conducted using simple and common tools such as human senses (sight,
taste, hear, smell, taste and gut-feelings), video camera, photo camera, tape
measure and a notebook. Optional tools include velometer and smoke tubes.

Next, all knowledge and
processes related to the hazardous agents are sought out using the central
dogma of risk assessment (Recognition, Evaluation and Control).

The sampling itself should be
done using standardized and validated methods (NIOSH, EPA, ASTM, etc.).

The extent of sampling should
be determined, whether personal (breathing zone) samples or area samples.

Next, the duration of sampling
should be determined, which could be  a
whole day, full-shift, partial shift, single samples, sequential samples, grab
or composite samples.

The worker to be sampled
should be with the worker with the 
highest exposure potential or a group of workers with similar exposure
due to the similarity of their tasks at the workplace.

The amount of samples taken
should also be determined.

The time of sampling should be
determined (day or night shift, winter or summer season, etc.)

Documentation should be made
at every sampling point; and this should include start and stop times,
environmental conditions, chronological log of work tasks, quantified
conditions during production, duration of shifts and break periods, use of PPE,
engineering controls, housekeeping habits and the state of workplace
ventilation.

PROGRAM DEVELOPMENT

Occupational hygiene programs
are made with several guidelines governing it. According to the province of
Ontario, all control programs must provide engineering controls, work practices
and hygiene facilities  to control a
workers exposure to a designated substance; methods and procedure should be put
in place to monitor airborne concentrations of designated substances and
measure workers exposure to the same; training programs should be organized for
supervisors and workers on the health effects of the designated substance and
the respective controls required. A typical Occupational Hygiene program,
therefore, should  include the following:

  • Version
    history
  • Purpose
    / objectives
  • Scope
    and application
  • Distribution
  • Definitions
    and abbreviations
  • Roles,
    responsibilities and accountabilities
  • Program
    management (Resources, commitment and program coordinator)
  • Risk
    assessments
  • Exposure
    monitoring plans
  • Occupational
    hygiene surveys (sampling strategy development, analytical services,
    documentation and reporting )
  • Occupational
    hygiene controls
  • Training
  • Related
    document / appendices
  • Quality
    assurance
  • Maintenance
    of standard operating practices (SOPs)
  • Annual
    summary report.

CONCLUSION

An occupational hygiene program is an important component of
workplace management. This ensures the protection of workers’ health, which
leads to better and greater productivity at the workplace.  The foundation of occupational hygiene
programs is to understand the principles that govern the program and knowing
how to apply the principles to various situations at the workplace. Proper
application and effective controls will assist in achieving the goal of
establishing a safe environment for workers to operate.

REFERENCES

  1. https://www.osha.gov/dte/library/industrial_hygiene/industrial_hygiene.pdf