NEBOSH Occupational Health Hazards by Terry Robson

7/28/2019 NEBOSH Occupational Health Hazards by Terry Robson

1/62

NEBOSH NATIONAL

GENERAL CERTIFICATE

Occupational health hazards


2/62

LEARNING OUTCOMES (I)

classification of occupational health hazards

(physical, chemical, biological, ergonomic)

commonly occurring occupational diseases andconditions arising from exposure to physical,

chemical, biological and ergonomic hazards

meaning of terms; toxic, harmful, corrosive,

irritant and the response of the body to substances

with these properties


3/62

LEARNING OUTCOMES (II)

the main routes of entry of hazardous substances

into the body

the significance of the form taken by a hazardoussubstance ie gas, vapour, mist, aerosol, smoke

fume, dust, liquid and solid

the concept of target organs and target systems

occupational exposure limits; distinction between

MELs and OESs


4/62

LEARNING OUTCOMES (III)

general principles and methods of air monitoring

methods that can be used for prevention and

control of hazardous substances, with particularreference to workplace ventilation systems

main requirements of the Control of Substances

Hazardous to Health Regulations 1994

precautions needed during the storage, transport,

use and disposal of dangerous substances


5/62

GENERAL ASPECTS OF

OCCUPATIONAL HEALTH

& HYGIENE

what types of agent might represent an

occupational health risk in the workplace?

how do we go about evaluating the severity

of the risk?


6/62

PRINCIPLES OF

OCCUPATIONAL HYGIENE Recognition/identificationof occupational

health hazards

Measurementof level or concentration

Evaluationof likelihood and severity of

harm Control strategiesavailable to reduce or

eliminate risk


7/62

RECOGNITION

chemicalliquids, fumes, mists vapours, gases, dusts

physicalradiation, noise, vibrations, temperature,

humidity

biological

bacteria, viruses, fungi ergonomic

body position, repetitive actions, work pressure


8/62

CHEMICAL HAZARDS

absorption then attack on organs or

metabolic processestoxic response

carcinogenic response

contact then attack on the surface of thebody

corrosive/irritant response

dermatitic/sensitisation response


9/62

BIOLOGICAL HAZARDS

exposure to biological agents resulting in

illness

types of biological agent include

bacteria

viruses

fungi


10/62

PHYSICAL HAZARDS

harmful energy absorbed by the bodys

structure energy derived from

mechanical sources

noise, vibration

radiation sources

ionising, non-ionising

thermal sources


11/62

ERGONOMIC HAZARDS

concerns the physical, physiological and

psychological relationships between peopleand work

specific areas include

perceptual responses

work rates and fatigue

man-machine interface

anthropometrics


12/62

MEASUREMENT

continuously

control strategy where the risk is high

intermittently

initial determination of hazard

spot measurement in an established process

routine check measurement


13/62

EVALUATION

harmful characteristics of the substance,

energy or condition involved

concentration, intensity orlevel of the

exposure to the harmful agent

time duration of the exposure


14/62

CONTROL

elimination

substitution

change of work method

change of work pattern

isolation and segregation engineering controls

personal protective equipment


15/62

ROUTES OF ATTACK ON

THE HUMAN BODY

route of entry

(reach an area of penetration of the

body)

process of entry(penetrate the outer cover of the body)


16/62

ROUTES OF ENTRY

inhalation

ingestion

skin pervasion

injection

implantation aspiration


17/62

PROCESS OF ENTRY

absorption

epidermislungs

gastro-intestinal tract

direct entry into the body


18/62

TOXICOLOGY- the study of poisonous materials and their effects

on living organisms

toxic substances

systemic

travel through thesystem

local

act only at the point ofcontact

cumulative not readily excreted

from the body

accumulated over aperiod of time

toxicity

LD50 to quantify the

effects of a toxic agentAcute Toxicity

harmful effect occurs

quickly (seconds,

minutes, hours)

Chronic Toxicity

harmful effect takes a

long time to appear

(months, years)


19/62

LOCAL AND SYSTEMIC

EFFECTS local effects

(confined to specific

area where contactoccurs)

skin

eye

respiratory tract

systemic effects

(occur at organs

distant from contactsite)

liver

nervous system

bone

blood-forming organs


20/62

DEFENCE MECHANISMS

OF THE BODY respiratory defence

physical filtration

phagocytosis

lachrymation

immune response

inflammatory response

fibrotic response


21/62

CHIP 2

Chemicals (Hazard Information and

Packaging for Supply) Regulations

1994

category of danger

indication of danger

symbol


22/62

HEALTH EFFECTS

CLASSIFICATION OF

HAZARDOUS SUBSTANCES

very toxic

toxic

harmful

corrosive

irritant

sensitising

carcinogenic

mutagenic

toxic for

reproduction


23/62

APPROVED SUPPLY LIST

general nature of the risk

(risk phrase)

causes severe burns precautions to be taken

(safety phrase)

keep out of reach of children


24/62

LABELLING

supplier information

name of substances or constituents

indication of danger

symbol

risk phrase

safety phrase


25/62

SAFETY DATA SHEETS

composition

hazards

first aid fire fighting

accidental release

handling/storage exposure controls

personal protection

physical properties

chemical properties stability/reactivity

toxicology

ecological information disposal


26/62

CATEGORIES OF

CHEMICAL AGENT

toxic, including carcinogenic

corrosive and irritant

dermatitic and sensitising


27/62

FORMS OF CHEMICAL

AGENT

solids

liquids

dusts

fibres

mists

gases

fumes

vapours


28/62

TYPES OF TOXIC EFFECT

respiratory irritants

chemical asphyxiants

haemolytic poisons narcotics

nervous systempoisons

metallic poisons

metallic and polymerfume fever

carcinogens

halogenatedcompounds

nitro-compounds

aromatic amines

polycyclic aromatichydrocarbons

natural carcinogens inorganic carcinogens

benzene


29/62

TOXIC AGENTS

physical form(s)

mode of entry to body

target organs symptoms of exposure

acute

chronic occupations at risk


30/62

COMMONLY OCCURRING

TOXIC SUBSTANCES lead

mercury

benzene

phenol

trichloroethylene

silaceous dust

asbestos

carbon monoxide


31/62

CORROSIVE AGENTS

destroy living tissue

acids and alkalis

injury through

contact with skin and eyes

inhalation

ingestion


32/62

DERMATITIC AGENTS

primary cutaneous irritants

contact dermatitis

at site of contact

recovery on removal of agent

cutaneous sensitisers

sensitisation dermatitis

initial sensitisation

trace contact enough to cause reoccurrence


33/62

SENSITISERS

respiratory system

occupational asthma

inhalation of antigen causes bronchialconstriction

sensitisation dermatitis

isocyanatestrace contact enough to cause reoccurrence


34/62

OCCUPATIONAL

EXPOSURE LIMITS (I) designed to control the absorption of

airborne contaminants into the body

measured in:ppm (parts of vapour/gas per million parts of air)mg/m3 (milligrams of substance per cubic metre of

air)

expressed as the concentration of an airbornesubstance averaged over a reference period15 minutes short term limit

8 hours long term limit


35/62

OCCUPATIONAL

EXPOSURE LIMITS (II) Maximum Exposure

Limit (MEL)

maximum permissible

concentration

has legal status

must not be exceeded

reduce exposure to as farbelow the MEL as

possible

Occupational Exposure

Standard (OES)

concentration at which

no evidence of harm

represents good practice

if exceeded, take steps to

reduce down to OES

OES represents adequate

control


36/62

OCCUPATIONAL

EXPOSURE LIMITS (III) long term limits

time-weighted average

concentration conc. x exposure time

averaged over 8 hours

designed to control

chronic effects

short term limits

time-weighted average

concentration conc. x exposure time

averaged over 15 mins

designed to control

acute effects


37/62

SAMPLING OF AIRBORNE

CONTAMINANTS (I)

Purpose

qualitative analysis

indicate presence ofand identity of contaminants

quantitative analysis

measure concentration and assess compliance

with standards


38/62

SAMPLING OF AIRBORNE

CONTAMINANTS (II) Types

spot or grab sample (stain tube)

taken at a single point at a particular time in thegeneral working atmosphere eg ozone monitoring

time averaged sample (dust sampling) taken over a period of time, analysed, and averaged

over that period (operators breathing zone)

continuous monitoring (direct reading) continually measured and giving a continuous

record of airborne contamination (can be used inconjunction with alarm systems eg toxic chemicals)


39/62

CONTROL PHILOSOPHY

Source Transmission Receiver

Elimination Shielding Remove worker

Substitution Distance Reduce exposure

Enclosure Dilution ventilation Enclose worker

Process change Reduce no of

workers

LEV Personal protective

equipment


40/62

VENTILATION

dilution ventilation

dilutes contaminant to

an acceptable level comprises fans set in

walls or roof

cheap and simple

limited application as a

control strategy

local exhaustventilation

captures contaminant

close to point ofgeneration

comprises hood,ductwork, filter,

fan,outlet good control of

hazardouscontaminants


41/62

DILUTION VENTILATION

(I) changes the whole workplace air over a

given time period ie air changes per hour

limit to circumstances where:exposure limit is high

low evaporation rate for liquids

slow evolution for gases

operators not close to the point of generation

substance is quickly carried away from theoperator


42/62

DILUTION VENTILATION

(II) rate of contaminant generation governs air

changes per hour required

density of contaminant governs position offans:density >1 (ie solvents) - low level fan in wall

density


43/62

LOCAL EXHAUST

VENTILATION (I) Hood or exhaust inlet

receptor hood

contaminant directed into a large hood by fanassisted draught

captor hood

contaminant captured by air flow close to point of

generation low pressure large volume flow

high pressure low volume flow (high velocity)


44/62

LOCAL EXHAUST

VENTILATION (II) ducting

straight with gentle bends and angled joints

sufficient air flow to prevent deposition ofsolids

access ports for cleaning and flow monitoring

filter or purifying systemcyclones, washers, electrostatic, bag filters


45/62

LOCAL EXHAUST

VENTILATION (III) Fans

axial flow fan airflow is parallel to the shaft of the impeller

compact and fits neatly into ductwork

centrifugal fan air enters the impeller then is discharged at right

angles

exhaust outletcareful location to avoid:

cyclic pollution

effects of weather of air disturbance


46/62

BIOLOGICAL HAZARDS

zoonosesanimal infections transmitted to persons in the

course of their work

bacilli infections such as Legionnaires or Weils

disease

fungiextrinsic allergic alveolitis

blood-borne infectionshepatitis B and AIDS


47/62

ZOONOSES

Brucellosis (bacterium)

cattle, pigs

Q Fever (bacterium)

cows, sheep

Orf(virus)

sheep

Psitticosis (bacterium)

poultry, birds

Anthrax (bacterium)

farm animals

Glanders

horses, donkeys, mules


48/62

CONTROL STRATEGIES

FOR ZOONOSES routes of entry

skin penetration

cuts, sores, abrasions

injection by bites contact with

conjunctiva of eye

inhalation

contaminated dust

ingestion contamination via hands

control strategies eliminate

immunisation

improve animal stock enclosure

infected aerosols

ventilation infected dusts from

wool, skin, hides hygiene disinfection

personal protectiveequipment


49/62

LEGIONNAIRES DISEASE

caused by inhalation of airborne dropletscontaining the legionella bacteria

pneumonia-type symptoms

manage the risk by:

identifying and assessing sources of exposure

contaminated sprays and aerosols

avoid conditions where legionella can proliferate(water temperature,stagnation, treatment)

persons at risk

susceptible persons ie hospital patients


50/62

WEILS DISEASE

caused by infection from rats

type of bacteria (Leptospira icterohaemorrhagiae)

enters body through cuts/abrasions of skin

jaundice-type symptoms

manage the risk by:

identifying and assessing sources of exposure

destruction of rat infestation immunisation, first aid, information, protective clothing

persons at risk

canal workers, sewer workers, abattoir workers

BLOOD BORNE


51/62

BLOOD-BORNE

INFECTIONS

hepatitis B (virus)

severe form of jaundice

infection through

contact with blood orbodily fluids

persons at risk includehealth workers andemergency services

protect throughpreventing puncturewounds, disinfectionand disposable gloves

AIDS (virus) debility of immune

system

infection throughcontact with blood orbodily fluids

persons at risk includehealth/social workersand emergency

servicesprotect through

preventing puncturewounds, disinfectionand disposable gloves


52/62

SUBSTANCES HAZARDOUS

TO HEALTH classified as dangerous to health under the

current CHIP Regulations

assigned a MEL or OES

biological agent

dust in a substantial concentration

any other substance which creates a

comparable health hazard


53/62

REQUIREMENTS OF

COSHH assess the risks to health arising from exposure

prevent or adequately control exposure

ensure that control measures are used andproperly maintained

monitor exposure and carry out appropriate

health surveillance ensure that employees are properly informed,

trained and supervised


54/62

COSHH ASSESSMENT (I)

which hazardous substances are present?

brought into the workplace

dusts, fumes, leakages finished products or wastes

who might be exposed?

employeescontractors

public


55/62

COSHH ASSESSMENT (II)

do they represent a significant risk?

hazardous properties (toxic, corrosive, irritant)

quantity used and frequency of usepossible routes of exposure (inhalation, contact)

possibility of exposure exceeding OEL

possibility of leakage, spillage or release

cleaning and maintenance operations


56/62

PREVENTING EXPOSURE

change the process or activity

the hazardous substance is not required or

generated

replace the hazardous substance with a safer

alternative use the hazardous substance in a safer form


57/62

CONTROLLING EXPOSURE

totally enclose the process

partially enclose the process and use local

exhaust ventilation

use general ventilation

use systems of work and handling

procedures that minimise spills and leaks

reduce the duration of exposure


58/62

MONITORING EXPOSURE

HEALTH SURVEILLANCE monitoring exposure

where serious risks if

controls fail

to confirm exposure

limits are not exceeded

to confirm that controls

are working properly

keep records

health surveillance

where exposure is

linked to a disease

which could occur and

can be detected

where employees are

working in a process

listed in schedule 5 andexposure could be

significant

RECORDING AND


59/62

RECORDING AND

REVIEWING THE

ASSESMENT record enough

information:

to show how decisions

on risks and

precautions were made

to clearly show the

responsibilities forimplementing the

precautions

review theassessment:

at no less than 5-yearlyintervals

whenever it is thoughtthat the assessmentmight not be valid

where there has been asignificant change inthe work

INFORMATION


60/62

INFORMATION,

INSTRUCTION AND

TRAINING inform, instruct and train employees about:

the nature of the substances and the risks

arising from exposurethe precautions that should be taken

give information and instruction on:

the purpose and use of control measuresuse of personal protective equipment

results of any monitoring or health surveillance

emergency procedures


61/62

DISPOSAL OF HAZARDOUS

SUBSTANCES (I) Safe Storage

segregate

control storage to prevent risks to employeesand others

keep hazardous and non-hazardous wasteseparate

ensure correct labellingkeep quantities to a minimum

separate incompatible hazardous wastes


62/62

DISPOSAL OF HAZARDOUS

SUBSTANCES (II) Transport

use correct type ofvehicle

inspect load prior totransport to check:

description of material

containment

labelling

documentation

transfer waste only toan authorised person

transfer must beaccompanied by

written documentation: identification

quantity

time and place oftransfer

details of current andintended holder

special waste requiresuse of a consignmentnote

Documents

NEBOSH Occupational Health Hazards by Terry Robson