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. • That’s 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 manufacturer’s 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 • Don’t 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