|
Module 3: Toxicology -
Section 6:
General Administrative Regulations and the Hazardous Chemical
Substances Regulations Revisited |
TOX 6.3: HCS Regulations |
B) THE REGULATIONS FOR
HAZARDOUS CHEMICAL SUBSTANCES (HCSS):
(Regulation
No. 5559, August 1995;
Government Gazette 16596, vol. 362).
(Click on the "Book" Regulations, and then open the "Book" Hazardous
Chemical Substances Regulations.)
Aim:
- To control health hazards to
workers arising from exposures to potentially hazardous chemical
agents/substances;
- HCS definition: any toxic,
harmful, corrosive, irritant or asphyxiant substance or a mixture of
substances for which an occupational exposure limit is prescribed or a
substance that can be shown to be harmful to health.
Scope:
- All employers, or
self-employed person carrying out work at a workplace;
- Excludes: workers exposed to
biological and radioactive agents, working on the mines;
- Superseded by Asbestos and
Lead regulations.
INFORMATION AND TRAINING:
Employer's duty to train and the worker's right to know:
Obligation
on employer to provide training on:
- contents and scope of the
regulations;
- possible sources of exposure;
- potential hazards to health
and to reproductive capabilities (male and female);
- protective measures,
including PPE, hygiene, engineering controls, work practices, etc.;
- necessity of environmental
monitoring and medical surveillance;
- emergency procedures.
Includes those transporting
HCSs (eg. drivers).
Responsibilities on both
employer to provide, and worker to accept training.
Obligation
on workers:
Places obligation on exposed
worker to obey lawful instructions relating to:
- control of exposures;
- wearing PPE;
- medical surveillance and
environmental monitoring
- hygiene measures;
- training and information.
EXPOSURE ASSESSMENT:
Introduces mandatory Risk
Assessment process for Employers. Have to identify:
- the HCS to which employees
potentially exposed;
- possible health hazards
associated with the process;
- in what physical form and
where HCS likely to be present;
- routes of exposure;
- nature of the work process
and the controls present.
Risk Assessment must be done in
consultation with health and safety reps or committee.
Repeat at least every
2 years,
or more frequently if change in process or inputs.
Triggers both environmental
monitoring and medical surveillance.
AIR MONITORING:
- Follows from Risk Assessment;
- Must be done by "Approved
Inspection Authority"
or equivalent;
- Must follow NIOSH sampling
method (OESSM): personal sampling;
- In consultation with the
safety reps or committee;
- Frequency:
12
months
for HCS with control-OEL
(Table 1
of HCS Regulations.
- Open
"Book" Regulations, "Book" Hazardous Chemical Substances Regulations,
then "Book" Annexure 1 and see "Occupational Exposure Limits - Control
Limits" page )
25
months
for HCS with recommended-OEL
(Table 2
of HCS Regulations. - Open
"Book" Regulations, "Book" Hazardous Chemical Substances Regulations,
then "Book" Annexure 1 and see "Occupational Exposure Limits -
Recommended Limits" page);
- If OELs exceeded, prompts
remedial action: control measures, PPE, respirator zone.
RESPIRATOR ZONE:
- Where not possible to reduce
environmental exposure below recommended OEL, can reduce personal
exposures by using respiratory PPE. Leads to establishing a Respirator
Zone.
- Demarcated as such, strict
controls: PPE, no food, smoking etc.
MEDICAL SURVEILLANCE:
Follows from Risk Assessment.
Prompted if:
- Exposure to substances with
known biological exposure indices (Table 3
of HCS Regulations. - open
"Book" Regulations, "Book" Hazardous Chemical Substances Regulations,
then "Book" Annexure 1 and see "Biological Exposure Indices" page);
- Substance not listed but
known to be a health hazard and can be monitored.
- Recommendation of
occupational health practitioner.
Includes:
- initial examination and
history (within 15 days of employment);
- appropriate clinical
assessment including special tests;
- follow up at set intervals
(at least 2
yearly).
Practitioner can remove worker
from exposure based on medical monitoring results (declare worker unfit
to work).
Forms of medical surveillance:
- Biological
monitoring:
measures the extent of absorption of HCS into the body eg. Blood lead,
urinary arsenic;
- Biological
effect monitoring:
measures the intensity of biochemical or physical damage due to
exposure eg. Red cell cholinesterase;
- Medical
screening:
detects any adverse health effects of HCS on the worker eg. Lung
function test for asthma.
Biological
Exposure Indices
(Table 3
of HCS Regulations):
- Reference
values
for guidance in the evaluation of potential health hazards;
- Indicates level of HCS (or
metabolite) detectable from a specimen of a healthy worker exposed to a
HCS to the same extent as a worker with inhalation exposure to an
OEL-TWA;
- Apply to 8-hr exposure 5
days a week;
- If measurements persistently
exceed the BEI, the cause must be investigated and proper action taken;
- Are NOT
intended for use as a measure of adverse effects or for diagnosis of an
occupational illness;
- See Table 3
of HCS Regulations: Meaning of
Notations:
A : identifiable population may have increased susceptibility to HCS
B : background (non-occupational sources) levels are included in the BEI
C : non-specific (but better correlate to exposure than specific tests)
D : quantitative interpretation of measured value is ambiguous.
RECORDS AND CONFIDENTIALITY:
- all records of medical,
environmental monitoring and risk assessments kept;
- records kept for at least 30
years;
- transfer of records to
regional DOL when workplace closes down;
- confidentiality maintained.
CONTROL OF HCSS:
Establishes hierarchy
of control
measures - PPE is a last resort:
HIERARCHY
OF CONTROLS SPECIFIED IN HAZARDOUS CHEMICAL SUBSTANCES REGULATIONS:
ADMINISTRATIVE
CONTROLS:
- Substitute.
- Limit amount used.
- Limit number of employees
exposed.
- Limit period of exposure.
ENGINEERING
CONTROLS:
- Enclose, automate or
separate process.
- Install local extraction
ventilation.
- Use wet methods.
WORK
PROCEDURES:
- Safe handling and disposal.
- Maintain equipment.
- Clean working areas.
- Take early corrective action.
IF
CONTROL IS NOT REASONABLY PRACTICABLE BY THE ABOVE METHODS:
PERSONAL
PROTECTIVE EQUIPMENT AND CLOTHING:
- Appropriate to hazard.
- Employees trained and
supervised in use.
- Careful maintenance,
storage, cleaning and disposal.
- Washing facilities, dual
lockers and change rooms.
(Section 12 deals with adequacy
of control equipment and need for audit of control measures every 25
months by an approved inspection authority).
Two
types of HCSs:
For substances with Recommended
OELs (R-OELs),
employer must aim to achieve levels below OEL as far as possible.
Temporary excursions can be tolerated if without significant risk of
exposure and does not signify failure of control mechanisms.
For substances with Control
OELs (C-OELs),
employer HAS
to keep levels below OEL. If cannot do so by engineering controls, etc,
can declare a Respirator Zone and use respiratory PPE to protect
workers (last resort). No excursions tolerated due to presence of
residual risk. Usually for known carcinogens and where no threshold of
effect identified.
STEL
(Short-term exposure limit) vs TWA (time-weighted average):
To differentiate between acute
and chronic effects of HCSs:
- TWA:
The long-term (8-hour) time weighted average exposure limit is intended
to control effects by restricting the total intake by inhalation over
one or more workshifts.
- STEL:
Short-term exposure limits (usually 15 minute) apply to HCS, which
produce effects with brief single or repeated exposures. If not STEL is
specified, rule of thumb is three times the long-term limit.
Dusts:
Not all dusts have been
assigned an exposure limit. In such cases personal exposure limits
assigned for:
- inhalable dusts: 10 mg/m3
- respirable dusts: 5 mg/m3
Skin:
- For certain substances
(lipid soluble), dermal route is a more significant route of absorption
eg. phenol, aniline, certain pesticides;
- Denoted as Sk
in Table 1
and Table 2
of HCS Regulations;
- Biological monitoring may be
more useful in such cases.
Sensitizers:
- Certain HCS may cause
sensitization in susceptible individuals and cause health effects after
very minute concentrations of the HCS eg. isocyanates;
- May be through respiratory
or dermal route;
- Result typically in asthma,
rhinitis, extrinsic allergic alveolitis, allergic contact dermatitis;
- Denoted as Sen
in Table 1
and Table 2
of HCS Regulations;
- Activities associated with
short-term peak concentrations may be more important.
Mixed
exposures:
- Majority of exposure limits
relate to single compounds;
- Effects may be independent,
additive or synergistic
- For additive effects
exposure limit defined as: C1/L1
+ C2/L2
+ C3/L3
+ ...< 1
(C: TWA concentration for a specific HCS, L: exposure limit for that
substance).
SUMMARY OF THE ASSESSMENT
CYCLE:
Timetable
of Actions Required by Hazardous Chemical Substances Regulations:
BASELINE |
THEREAFTER |
1. Exposure risk assessment |
Immediate 1 |
2-yearly |
2. Air monitoring 2,
3
Control limit substances
Recommended limit substances |
Immediate
Immediate |
Annual
2-yearly |
3. Review of control measures by
approved
inspection authority |
Immediate |
2-yearly |
5. Medical surveillance 2 |
Immediate |
2-yearly 5 |
Notes:
1. And at change in use or breakdown of controls.
2. Contingent on findings of exposure assessment.
3. Carried out or verified by an Approved Inspection Authority.
5. Or otherwise at the discretion of the occupational medicine
practitioner. |
PERSONAL PROTECTIVE EQUIPMENT
(PPE):
PPE is clearly last resort
after engineering, administrative and other controls. Obligation placed
on employers to:
- provide respiratory and skin
PPE as required;
- ensure PPE in good working
order and well maintained;
- accompanied by training of
workers;
- supported by adequate
storage, cleaning and changing facilities.
(Section 5 places obligation on
worker to use the PPE).
OTHER: PROHIBITIONS, LABELLING
OF HCSs:
Smaller section of the
Regulations deal with specific prohibitions (ban use of compress air,
control of smoking and eating by workers, etc.). Labeling, packaging
and transport of HCS dealt with by referring to SABS codes.
Environmental emissions and disposal of HCSs in terms of environmental
legislation.
ISSUES AND PROBLEMS:
- No statutory protection
against job loss on medical grounds - left to general labour
legislation and section 26(2) of OHSA, which prevents victimisation.
- Does not address mixtures of
HCSs well. Assumes either additive or no interaction. Schedules do not
list whole formulation.
- Not well suited to HCS whose
main route of absorption is dermal. Relies on air levels. Not suited
for working in an open environment.
- Not explicit on Risk
Assessment process.
- Confusion around definition
of occupational health practitioner.
- Shortage of skills to
provide sufficient "approved inspection authorities".
- Shortage of enforcement
personnel.
Postgraduate Diploma in Occupational Health (DOH) - Modules 3:
Occupational Medicine & Toxicology (Basic) by Profs Mohamed
Jeebhay and Rodney
Ehrlich,
Health
Sciences UCT is licensed under a
Creative
Commons Attribution-Noncommercial-Share Alike 2.5 South Africa License.
Major contributors: Mohamed Jeebhay, Rodney Ehrlich, Jonny Myers,
Leslie London, Sophie Kisting, Rajen Naidoo, Saloshni Naidoo. Source available
from here.
For any updates to the material, or more permissions beyond the scope
of this license, please email healthoer@uct.ac.za
or visit www.healthedu.uct.ac.za.
Last updated Jan 2007.
Disclaimer note: Some resources and descriptions may be out-dated. For
suggested updates and feedback, please contact healthoer@uct.ac.za.