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Chemical hazards

VIEWS: 51 PAGES: 21

									OCCUPATIONAL SAFETY and HEALTH




               CHEMICAL
               HAZARDS
                     Quiz
    WRITE YOUR STUDENT SECTION IN YOUR
                     ANSWER!
1. What are the basic steps that should be taken
   in order to ensure a safe and healthy
   workplace and prevent accidents?
      (3 marks)

2. List down 3 types of hazards together with
   example                             (6 marks)
                   INTRODUCTION
 Chemicals provide hazards due to the toxic, flammable,
  explosive, corrosive, combustible and reactive hazards
 In order to manage chemical materials more efficiently,
  we should know the characteristics of the chemicals
  and also the nature of the materials that need to be
  stored and the risks involved
For prevention, we need
 to make its manufacture,
 storage, handling and use            160-200
                                               Carcinogens
                                                  Hazardous
 safely                             3,500-8,000 substances
Information on hazardous         70,000-80,000       Marketed
                                                      chemicals
 chemicals are usually              5-7 million
 available in Material             Known
                                   chemicals
 Safety Data Sheet (MSDS)
 or labels
       SIGNIFICANT DISASTERS
1. Flixborough, England, 1974
 • Rupture inadequately supported bypass pipe
 • Vapor cloud 30 ton cyclohexane
 • Explosion & fire inventories (10 days)
 • 28 killed & 89 injured
2. Seveso, Italy, 1976
  • Reactor out of control
  • Vapor cloud 2 kg dioxin
  • 700 affected, 730 evacuated
3. Bhopal, India, 1984
  • Not operating scrubber &
    flare system
  • Vapor cloud 25 ton toxic MIC
  • 2000 killed & 20,000 injured
4. Bright sparklers, Sungai Buluh, Selangor
            CLASSIFICATION of chemical
1. Gases
                           hazards of its own
 Volatile & no definite shape or volume
 The hazards of gases can be due the method used for
  confinement of the gas.
  a) Compressed gases – hazardous because of the stored
     energy
  b) Liquified gases – hazardous because of extreme low
     temperatures of the substance
 The gas may have toxic, flammable, corrosive or
  oxidising properties
2. Flammable liquids
Liquids that can produce flammable at ambient
 temperatures and are potentials sources of fire
Other hazards may include toxicity and corrosives
3. Explosive substances
 In forms of solid, liquid or mixture which is capable by
  chemical reaction
 Contain both fuel & oxidant can function
  independently of the nature of their surrounding
 Eg. : dynamite & carbide

4. Corrosive substances
 Will attack skin & materials such as wood or metals
 Eg. : sulphuric acid, caustic soda etc

5. Oxidising agent
 Supply oxygen - readily support & maintain
  combustion that increase the rate at which the fire
  will develop
 Eg. : Sodium chlorate
6. Flammable solids
Readily ignitable solids that cause fast fire propagation
 once ignited
Eg. : magnesium, plastics, flour etc
7. Toxic substances
Very hazardous to health when inhaled, swallowed or in
 contact with the skin and may lead to death
Eg. : Aniline, arsenic, benzene, beryllium, cyanide etc…

IDENTIFICATION of hazardous chemical
1. United nation classification
Since chemical products are traded and transported
 world wide, The United nation Committee of Experts on
 Dangerous Goods came out with a recommendation for
 the Transport of Dangerous Goods in 1956
Most classified chemicals can be identified from labeling
 There are 9 classes of dangerous goods;
  1) Explosives – classes 1.1 ~ 1.6
     • Eg. : class 1.1 : TNT, class 1.2 : Bombs etc…
  2) Gases - classes 2.1 ~ 2.3
     • Eg. : class 2.1 : acetylene, L.P.G etc…
  3) Flammable liquids - classes 3.1 ~ 3.4
     • Eg. : class 3.1 : paint, petrol etc…
  4) Flammable solids - classes 4.1 ~ 4.3
     • Eg. : class 4.1 : phosphorous etc…
  5) Oxidising agents & organic peroxides – class 5.1 & 5.2
     • Eg. : class 5.1 :ammonium nitrate etc…
  6) Poisonous & Infectious subs.- classes 6.1(a)~ 6.2
     • Eg. : class 6.1(a) : cyanide, lead compounds etc…
  7) Radioactive substances
     • Eg. : Uranium and radioisotopes
  8) Corrosives
     • Eg. : Hydrochloric acid, caustic solutions etc…
  9) Misc. dangerous substances
     • Aerosols, polyester beads etc…
2. UN numbering
 UN committee also came out with a numbering system
  for each hazardous chemical
 More specific to identify similar chemical with different
  name
 Only applied to hazardous chemicals
 Eg. : - sodium hydroxide = caustic soda 1823
        - acetone  1090
        - sulphuric acid  1830
        - acetylene  1001 etc…

3. HAZCHEM scale
 Developed by health & safety executive of United
  Kingdom is address to the emergency and fire brigade
  personnel
 It gives them a ready method of controlling a spillage
  or fire arising from hazardous chemicals
   MATERIAL SAFETY DATA SHEETS
For all hazardous chemicals
  Readily available during normal work hours
Immediately accessible during emergencies
Providing the MSDS:
  •Initial shipment
  •First shipment after update
Failure to provide the MSDS
  •DOSH (Dept of safety & health) investigates when
    suppliers or manufacturers refuse to provide MSDSs
Remote work sites
  •MSDS may be kept at central location
  •Must be readily available
  •Must be immediately accessible
Kept in any form
  •Paper
  •Computer
                             MATE R IAL SAF ETY DATA S H E ET

                                                           PROPANE
================================================================================
                                             SECTION I - Product Identification
================================================================================
 PRODUCT NAME:               PROPANE
 FORMULA:                    N/A
 FORMULA WT:                 N/A
 COMMON SYNONYMS:            N/A
 ================================================================================
                                          SECTION II - Hazardous Components
================================================================================
  PROPANE
================================================================================
                                              SECTION III - Physical Data
================================================================================
BOILING POINT:               -44F                               VAPOR PRESSURE(MM HG):         N/A
MELTING POINT:               N/A                                VAPOR DENSITY(AIR=1):          1.55
SPECIFIC GRAVITY:            N/A                                EVAPORATION RATE:              NA
   (H20=1)                                                         (BUTYL ACETATE=1)
SOLUBILITY(H20):             N/A                                % VOLATILES BY VOLUME:         100
APPEARANCE & ODOR:           COLORLESS-ROTTEN EGG ODOR.
             =================================================================================
                                      SECTION IV - Fire and Explosion Hazard Data
=================================================================================
FLAMMABILITY CLASSIFICATION:                              UNK
FLASH POINT:                                              -156F
FLAMMABLE LIMITS:                                         UPPER - 9.5 %      LOWER - 2.1 %
FIRE EXTINGUISHING MEDIA:               STOP FLOW OF GAS OR OXYGEN
SPECIAL FIRE-FIGHTING PROCEDURES:       USE WATER TO COOL TANK
UNUSUAL FIRE AND EXPLOSION HAZARDS:     AUTO IGNIT TEMP 874F;HEAVIER THAN AIR
                             (VAPOR DENSITY 1.5) MAY TRAVEL A
                                                          CONSIDERABLE DISTANCE TO AN IGNITION
                             SOURCE AND FLASHBACK
================================================================================
                                            SECTION V - Health Hazard Data
================================================================================
EFFECTS OF OVEREXPOSURE: POSS FREEZ BURN;MOD CONCENTRATION
                             W/AIR CAUSES UNCON
MEDICAL CONDITIONS PRONE
TO AGGRAVATION BY EXPOSURE:             UNK
PRIMARY ROUTE(S) OF ENTRY: INHALE
EMERGENCY AND FIRST AID PROCEDURES:     INHALE/FRESH AIR
================================================================================
===============================================================================
                                                              SECTION VI - Reactivity Data
===============================================================================
STABILITY:            STABLE                   HAZARDOUS POLYMERIZATION: WILL NOT OCCUR
CONDITIONS TO AVOID:                        NA
INCOMPATIBLES:                              NONE
DECOMPOSITION PRODUCTS: NONE
===============================================================================
                                                    SECTION VII - Spill and Disposal Procedures
===============================================================================
DISPOSAL PROCEDURE:
VENT TO ATMOSPHERE IN FLAME FREE, SPARK FREE AREA OUTDOORS
OTHER PRECAUTIONS:
NONE
===============================================================================
                                                         SECTION VIII - Protective Equipment
===============================================================================
VENTILATION:
 NA
RESPIRATORY PROTECTION: NONE W/NORMAL USE
EYE PROTECTION:                             NONE
SKIN PROTECTION:                            NONE
OTHER EQUIPMENT:                            NONE
HYGIENIC PRACTICES:                         NONE
===============================================================================
                                                  SECTION IX - Storage and Handling Precautions
===============================================================================
SPECIAL PRECAUTIONS:
  TEMPS <120F IN WELL VENTED AREA AWAY FROM SPARK AND FLAME
===============================================================================
                                         SECTION X - Transportation Data and Additional Information
===============================================================================
N/A
 --------------------------------------------------------------------------------
(TM) and (R) : Registered Trademarks
N/A = Not Applicable OR Not Available
The information published in this Material Safety Data Sheet has been compiled from our experience and data presented
in various technical publications. It is the user's responsibility to determine the suitability of this information for adoption
of necessary safety precautions. We reserve the right to revise
Material Safety Data Sheets periodically as new information becomes available.
Copyright by Manufacturer
LICENSE GRANTED TO MAKE UNLIMITED COPIES FOR INTERNAL USE ONLY
by OREGON STATE UNIVERSITY
            EXPOSURE to the chemical
 Acute
  • Short term period between exposure and onset of
    symptoms
 Chronic
  • Long time period between exposure to an agent and the
    onset of symptoms
 Unit of concentration;
  •   ppm - parts per million
  •   mg/m3 -milligrams per cubic meter
  •   Mppcf -millions or a particle per cubic foot
  •   f/cc - fibers per cubic centimeter
 Exposure limits;
  • TWA -takes into account variable exposure through a full
    shift, 8 hour work day
  • STEL - limit of exposure for a short period, 15 mins
  • CEILING - absolute maximum level of exposure
Standard used for chemical threshold limits
 will be determined by;
   • OSHA (Occupational Safety and Health Administration)
   • NIOSH (National Institute of Occupational Safety and Health)
   • ACGIH (American Conference of Governmental Industrial Hygienists)
 Examples of threshold limits value
                                              TLV-TWA (ppm)

                   Chlorine                           0.5

                Formaldehyde                           1
              Carbon Monoxide                         25

                  Turpentine                         100

               Methyl Alcohol                        200

                   Acetone                           1000
Important features
 CHEMICAL         SYNONIMS           PEL      PHY.           INCOMP.              FIRST AID
   NAME                             (ppm)     DESC.
Ammonia            Ammonia           50     Colourless        Strong         Eye : wash immed.
                   anhydrous                  liquid      oxidizers, gold,   Skin : water flush
                                                             halogens        Breath : art. resp.
Benzene         Coal tar, naphta,     1     Colourless         Strong        Eye : wash immed.
                 phenyl hydride               liquid         oxidizers,      Skin : soap wash
                                                              chlorine       Breath : art. resp.
                                                              bromine        Swallow : no vomit
Chloroform      Trichloromethane     50     Colourless    Active metals,     Eye : wash immed.
                                              liquid       caustic soda      Skin : soap wash
Cyanide           Potassium           5     White solid   Strong oxidizers   Eye : wash immed.
                    cyanide                               Such as nitrates   Skin : soap wash
                Sodium cyanide                            chlorates, acids   Breath : art. resp.
                                                             acid salts      Swallow : water vomit
Sulfuric acid     Oil of vitriol      1     Dark brown,      Organics,       Eye : irr. immed
                                              odorless       chlorates       Skin : water flush
                                                             carbides        Breath : art. resp.
                                                                             Swallow : water vomit
Toluene         Phenyl methane       200    Colourless    Strong oxidizers   Eye : irr. immed.
                methyl benzene                liquid                         Skin : soap wash
                                                                             Breath : art. resp.
                                                                             Swallow : no vomit
        PROTECTION from chemicals
 Chemical can affect health in many ways & commonly
  identified by inhalation, absorption & ingestion
     Type            Entry          Method of prevention
Inhalation    mouth, nose     Ventilation, hoods, equipment
Absorption    skin            Protective clothing
Ingestion     mouth, stomach Rules on eating, smoking etc

The best practice;
  • Get a copy of the Material Safety Data Sheet (MSDS)
    and learn all about the properties of the chemical.
  • Has is got a UN number, if so classified as dangerous.
  • Then look for the hazard warnings, hazard symbols,
    risk and safety phrases.
  • Always follow instruction.
  • Don’t be over confident!
                            DO
   Read the container label and MSDS before starting a job
   Keep your work area CLEAN
   Use protective clothing and equipment
   Follow safety rules
   Use approved and labeled containers for storing and
    transporting hazardous materials
   Follow company instructions when removing hazardous
    materials from containers
   Make sure there is enough ventilation explosive
    materials away from heat
   Check that containers and hoses are in good working
    condition
   Take safety training seriously
   Store chemicals properly. Keep chemicals that may
    react with each other separate. Check the MSDS
                     DON’T
DON’T leave containers open when not in use.
DON’T siphon by mouth.
DON’T depend on a “funny smell” to detect hazardous
 gases in the air some are odoriess.
DON’T mix a chemical with another substance even
 water unless you are instructed to. Even then, follow
 instructions
DON’T breathe gases produced from chemical reactions.
DON’T pour water into acid.
DON’T smoke, eat, or drink around hazardous
 substances.
DON’T store hazardous chemicals next to each other
 without checking the MSDS for possible reactions.
DON’T wear contact lenses around toxic vapors.
DON’T cut corners on hazardous substances handling
 procedures.
Chemicals safety symbols/signs
      Poisonous
      The poison symbol is self-explanatory. Whereas most chemicals
      are fairly dangerous if ingested or inhaled, many of these are
      dangerous even on contact.


      Flammable or extremely flammable
      Chemicals to be stored in flame-resistant cupboards. Volatile
      solvents can be a particular problem as they are prone to spread
      around from unsealed containers. This also covers pyrophoric
      materials (that catch fire spontaneously on exposure to air).

      Corrosive
      Will destroy or irreversibly damage another substance with
      which it comes in contact. The main hazards include damage to
      eyes, skin and tissue under the skin, but inhalation or ingestion
      are also very risky. Avoid contact, and bear in mind that these
      can (under some ciurcumstances) rust chemical cupboards.
Oxidising chemical
Oxidising chemicals are materials that spontaneously evolve
oxygen at room temperature or with slight heating, or that
promote combustion. To be kept away from flammable
chemicals at all costs!

Environmental hazard
Relatively rare with laboratory chemicals (most of which pose
some environmental hazard if not got rid of correctly), these
require particular care to be taken on disposal.


Irritant or HarmfulThis symbol covers a wide range of
(sometimes relatively minor) hazards - with precautions such as
avoid contact with the skin, do not breathe, etc. - best to refer to
relevant data sheet for details.



Explosive
Again, fairly self-explanatory, though fairly seldom seen in the
average lab. Bear in mind that noise and movement can also
trigger explosion (not just sparks/flames!).
THE END

								
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