Chemical Management And Use

1
Chemical Management And Use

• Session 5
• Laboratory Safety Training

2
Chemical Incompatibilities

• Store chemicals according to hazard class.
• Acids must be stored away from bases and
  flammables.
• Review CHP appendices LBSF5 and 6, and page 244
  of the CRC book.
• Flammable gases must be 20 ft from oxidizers.
• Place spark or flame generating equipment away
  from flammables.

3
Labeling

• Chemical inventory lists MUST be kept current.
• Date all chemicals upon arrival
• especially peroxide formers
• see peroxide list in CHP appendices
• Color coding schemes can be used.

4
Ordering Chemicals

• Only order the amount of product that you can use
  in one month.
• Bigger is NOT cheaper in the long run!
• Prepare orders early and thoughtfully.
• Check to see if recycled solvents are available.
• Conduct Hazard Analysis
• Obtain required prior approval(s) for use of
  chemicals

5
Prior Approval is Required for Special Chemicals

• Radioisotopes
• CDC Select Agents
• Etiological Agents
• Require special lab modifications

6
Prior Approval is Required for Special Chemicals

• Acute Toxics
• Controlled substances
• require secure storage
• require exact tracking of quantities

7
Flammable Liquids

• Chemicals with flashpoints lower than 37.8 C.
• Flashpoint the lowest temperature at which a
  liquid has sufficient vapor pressure to form an
  ignitable mixture with air at the surface of the
  liquid.
• Must be stored in flammable storage cabinets.

8
Flammable Liquids

• Most organic liquids have flash points below room
  temperature.
• Ignition (autoignition) is the minimum temp
  required to initiate self sustained combustion
  independent of a heat source.

9
Flammable Liquids

• The lower this temp the greater the potential for
  a fire started by typical laboratory equipment.
• A spark is not necessary for ignition when a
  flammable vapor reaches its autoignition temp.
• EX Carbon disulfide has an autoignition temp of
  90C and can set off by a warm surface like a
  light bulb or a steam line.

10
Limits of flammability

• Each flammable gas or liquid has a range of
  flammability beyond which ignition will not
  occur
• LEL- the lower explosive limit where the liquid
  concentration ( by volume) of the fuel in air is
  too lean to burn.
• UEL - the upper range where the concentration is
  too rich to burn.

11
Limits of flammability
Acetone
2.6
12.8
LEL
UEL
Flammable Range
Too Lean
Too Rich
The range becomes wider with increased
temperature and in the presence of oxygen!
12
Limits of Flammability Cont.

• An acetone spill outside the fume hood could very
  quickly reach the flammable range, spread, find
  an ignition source (any piece of electrical
  equipment) and flash back to create an explosion.
  
• Thats another reason why pouring of any chemical
  should always occur inside the fume hood!

13
Bonding and Grounding

• Containers of flammable liquids should be bonded
  (attached to the conductive surface of the
  container you are pouring into) and grounded
  (attach a copper wire from the drum to the
  ground) when pouring to discharge static
  electricity.
• This especially important in cold dry atmospheres
  when pouring more than 5 gallons of a flammable
  liquid.

14
Corrosives

• Includes a broad definition and group of
  chemicals but all will potentially cause tissue
  destruction. Can be high or low pH material.
• Lab injuries from these chemicals are very common
  and can be particularly destructive to the eyes
  and mucous membranes (upper respiratory tract).
• Skin injuries can be painful slow to heal.

15
Bases

• Strong Bases- skin contact is potentially more
  dangerous than acids. Bases do not coagulate
  protein like acids (impeding penetration),
  resulting in deeper tissue skin penetration
  before it is apparent resulting in severe
  slow-healing burns. Likewise inhalation of high
  concentrations can cause delayed severe pulmonary
  edema.
• Appropriate glove and goggles should be worn when
  pouring bases.

16
Acids

• Always pour acid into water not the reverse.
• Always wear safety glasses and rubber (not latex
  or vinyl) when pouring. Strong acids require
  rubber aprons.
• Always use secondary containers when
  transporting. Store on lower shelves if corrosive
  cabinet is not available.
• Can cause painful burns.

17
Acids Cont.

• Inorganic acids (Sulfuric Acid, Nitric Acid,
  Perchloric Acid, Hydrochloric Acid) are more
  dangerous than organic acids but burns can be
  deeper with the latter.
• Poor transfer and housekeeping will corrode all
  metal surfaces and equipment.
• Should be stored in plastic trays.

18
Perchloric Acid

• Never heat in an ordinary fume hood. Must be used
  in a specially designed perchloric acid hood with
  a wash-down system.
• Strong oxidizer when heated.
• Never let in contact with wood or metal surfaces
  or floors.
• Never permit it to be in contact with organic
  material or flammable liquids.

19
Perchloric Acid

• Digest organic matter first in nitric acid then
  add perchloric.
• Never heat with sulfuric acid, to prevent the
  formation of explosive anhydrous perchloric acid.
• Never allow to dry
• can form explosive perchlorates.
• Neutralize spills, wipe up with wet wipes keep
  them wet or material may combust. Place wet
  wipes in a ziplock plastic bag place in flammable
  waste disposal can.

20
Hydrofluoric Acid

• Extremely corrosive to all tissues will cause
  deep-seated burns.
• Readily penetrates the skin causing soft tissue
  damage and decalcification of the bones.
• HF vapor can cause permanent lung damage and
  blindness.
• Brief exposure (5min) of 50ppm can be fatal to
  humans. Spills of 70 on an area the size of your
  hand are fatal. Contact with solutions of 1-20
  may not be felt for several hours and can still
  be fatal.

21
Hydrofluoric Acid

• HF reacts with glass ceramics and some metals
  forming H2 gas.
• It should be stored in secondary containers and
  only used by trained personnel.
• Calcium Gluconate gel must be on hand in all labs
  that use HF.
• HF fatality

22
Peroxide Formers

• Organic peroxides are one of the most hazardous
  substances used in the lab. The are low-power
  explosives sensitive to friction, heat, sparks or
  other accidental initiation.
• All are extremely flammable, many will autoxidize
  when exposed to the oxygen in air. Ether is
  especially prone to this.

23
Peroxide Formers

• Classes of peroxidizable chemicals
• ACS recommends disposing of all cyclic ethers
  within 3 months of receipt.
• Store peroxide formers away from heat and light
  in closed vessels from the manufacturer.
• Date all bottles as they arrive.

24
Peroxide Formers

• Follow the manufacturers recommendations on the
  minimum safe temp for storage. Do not store
  below this temp! Do not store diethyl ether in a
  refrigerator or a freezer, precipitates could
  form.
• Limit the quantity kept in the lab to smallest
  amount necessary for immediate use If a potential
  peroxide former is cloudy, has formed crystals or
  there is a suspicion do not touch. Call OSEH to
  have it removed.

25
Peroxide Formers

• Dont return unused portions to the original
  container.
• Never use metal spatulas only plastic. Can reduce
  sensitivity by dilution with mineral oil, never
  with acetone or other ketones.
• Never use glass containers with screw cap lids or
  glass stoppers, only plastic bottles or sealers.

26
Personal Protective Equipment

• Respiratory protection
• Dust masks
• Use only when exposure is PEL
• Half Face
• Full face
• Cartridges
• Self-Contained Breathing Apparatus
• SCBA

27
Personal Protective Equipment

• Eye Protection
• Safety Glasses meet ANSI Z87.1
• Safety Goggles
• Face Shields
• Contact Lenses

28
Personal Protective Equipment

• Gloves
• Clothing
• Shields