Working with Hazardous Chemicals Personal protective equipment Special

Working with Hazardous Chemicals Personal protective equipment Special conditions Routes of chemical exposure

Part 1: • Personal Protective Equipment (PPE)

Standard Lab Dress • • Have as little bare skin as possible No loose hair, necklaces, neckties No loose clothing (i. e. sleeves) No rings, watches • Key: Easy to remove clothes or wash skin if chemical contamination or fire occur

Proper use of lab coats • Always wear lab coats. – To protect skin and clothes from contamination – To prevent spread of contamination outside of lab • Won’t protect against corrosives – USE APRON • Fit: should not be too loose, unbuttoned, or have rolled sleeves Should not be laundered at home. Should not be worn outside of lab. http: //cdn. shopify. com/s/files/1/0041/4632/files/new-lab -coat. jpg? 1263858434

Appropriate Lab Footwear • CLOSED TOE. NOT WOVEN. – Protect against spills – Broken glass • Lab shoes vs. street shoes – Disposable shoe covers http: //www. reef-sandalsonline. com/images/reef_convertible_sandal. jpg http: //www. bomir. com/images/zerocharge/a-sc 1. jpg

Laboratory Gloves: Purpose • Gloves serve a wide range of purposes: – protection against chemicals – against biologicals – against punctures – against temperature extremes • No single glove can do all this and still be flexible enough to use in fine manipulations

Choosing Laboratory Gloves • Consult chemical resistance chart for glove – degradation rate: tendency of chemical to physically change properties of glove on contact – permeation rate: tendency of chemical to penetrate – breakthrough rate: time required for chemical spilled on outside of glove to be detected on inside surface

Proper Glove Use • Can double glove with two different glove types for extra protection • Choose thickest gloves which allow dexterity to perform task http: //www. ansellhealthcare. com/images/Product. Images/undergl ove_1. jpg

Proper Glove Use (con. ) • • • Check for holes or tears Keep cuts bandaged Keep nails short Make sure gloves cover wrists Change regularly and after contact with hazardous materials Remove gloves so that skin contact does not occur with outside glove surface • Wash hands after glove use or if contamination is expected • Do not touch doorknobs, lights, etc. with gloves on

Eye Protection • Safety glasses with side shields – small chemical splashes http: //www. cordless-drills. net/images/pictures/ao-safety-seeproplus-safety-glasses. jpg • Goggles – large splashes and caustics • Face shields – explosion http: //www. dryeyepain. com/Safety-goggle. jpg • good for UV protection. Wear eyewear underneath. http: //www. labsafety. com/images/xl/TASCO-9000 -Face-Shield. LSS-_i_LBN 67630_01 S. jpg

Other types of PPE • Ear protection – ear plugs or ear muffs – protect against sonication noise http: //di 109. shoppingshadow. com/images/di/32/6 a/4 f/436437597 • Masks 863504 c 62796846387041756 b 6877 -149 x 149 -0 -0. jpg – filter dust and aerosols – protect against minor splashes – Will not protect against biological infectious agents http: //www. rosemarydrive. com/renovation/safety/classicdustmas k. jpg

Other PPE (con. ) • Respirators – protect against toxic fumes – must have training to use • Self-contained breathing apparatus – contains own air supply – when user must work in highly toxic fumes http: //images. plant-care. com/respirator-2. jpg http: //www. dalmatianfire. com/Images/Industrial/Pro. Air%20 Evoluti on. jpg

Part 2: • Working in special conditions

Working with glass • Check glassware prior to heating or centrifuging or otherwise stressing glass • Place mat in bottom of sink prior to washing glassware

Working with sharps • Never leave these sitting on benchtops where someone may accidentally get hurt • Always scrape or cut away from body • Recap needles by placing cap on benchtop and inserting needle to prevent punctures • Dispose of sharps in specially labeled container http: //sunsetscavenger. com/images/sharps. jpg

Working with gas cylinders Gases mostly non-toxic and nonflammable Danger comes from risk of explosion or falling • Wear eye protection • Attach cylinders to wall • Transport cylinders one at a time in a cart secured by a strap • Keep safety cap on during movement • Know about hazards of gas prior to use • Never direct stream of gas at anyone http: //www. med. cornell. edu/ehs/updates/1. 4

Working with heat • Bunsen burners • don’t leave flame unattended • Don’t leave flame where someone may reach over it • Keep flame visible • Hot plates • Leave note that it is hot after use • Hot liquids • Never heat a closed container • Watch for superheated liquids • In case of minor burns, flood skin with cold water for 10 – 15 minutes

Laboratory Fires Most common source of fire = ignition of flammable organic liquids and vapors http: //pubs. acs. org/cen/img/83/i 21/8321 gov 2_opening. tifcxd. JPG

Preventing Laboratory Fires • • Keep minimum amount of flammables Keep open solvents away from flame Store flammables in appropriate cabinets Use water baths or hot plates instead of Bunsen burners Limit ignition sources: sparks, static electricity Never leave flame unattended Marked heated hot plates Reduce electrical hazards

Extinguishing Laboratory Fires • NEED FUEL, HEAT, OXYGEN TO GET FIRE – TAKE ONE AWAY AND IT EXTINGUISHES http: //www. cedars-sinai. edu/Medical-Professionals/Resources-for -Physicians/Safety/Images/371590_fire_triangle. gif

Types of Extinguishers • Class A = paper, cloth, wood – Use water or multipurpose dry chemical • Class B = organic solvents, gases, paints – DO NOT USE WATER – Carbon dioxide or foam to remove oxygen • Class C = electrical – DO NOT USE WATER. May cause electrocution. – Use carbon dioxide or dry foam • Class D = combustible metals – Need special extinguisher approved for source metal.

Working with extreme cold • Contact with extreme cold (-78 degrees Celsius or below) causes skin burns – Cryogenic liquids can not be used with ordinary lab glass or plastic. Stored in Dewar vacuum glass flasks. • Dry ice = solid – Use eye protection to chip large blocks – Do not lean too far into chest for long periods. This can cause suffocation. • Liquid nitrogen (-198 degrees Celsius) – Very hazardous to dispense. Never do this without training.

Working safely with electricity • • Keep hands dry Be sure equipment is grounded Keep area under equipment dry Check cords to see if in good condition

Working with UV light UV-B AND UV-C light in labs can damage skin and eyes • • • Always wear approved eye protection Cover skin Do not direct UV light at coworkers Use a face shield if necessary Use germicidal lamp only when area not in use

Working with autoclaves Autoclaves are sterilization devices that use high pressure and very high temperature • Do not use chipped glassware • Be sure plastics are autoclavable • Make sure inside of autoclave is at atmospheric pressure before opening door • Wear eye and hand protection • Stand back when opening door • Release pressure slowly for liquids to prevent boilover • Let autoclaved liquids sit 10 minutes prior to removal to prevent boilover

Part 3: • Routes of entry for chemical exposure

Routes of entry for toxic chemicals • • Inhalation Skin and eye contact Ingestion Injection • Most likely in lab = skin contact and inhalation

Measuring chemical toxicity Chemicals differ in: – Toxic dose – Route of toxicity • LD 50 (lethal dose – 50%) – amount of chemical causing death in 50% of test animals – LD 50 is recorded in grams chemical / kilograms body weight http: //www. chem. duke. edu/~bonk/Chem 8304/LD 50. GIF

Levels of toxicity • LD 50 depends upon route of exposure – High toxicity = <500 milligrams / kg by ingestion or injection – High toxicity = < 1 gram / kg by skin contact • LC 50 (lethal concentration) – concentration of chemical in air that will kill 50% of exposed animals. – Expressed in ppm. – <2000 ppm inhalation = highly toxic.

Toxicity by inhalation Reactions range from mild discomfort to burning to asphyxiation • For volatile chemicals, can NOT estimate exposure by odor. Therefore, you should limit your exposure by working in a fume hood.

ACGIH limits of exposure • American Conference of Governmental Industrial Hygienists (ACGIH) has set limits of exposure – OSHA adopted these and set as regulated limits. • Threshold Limit Value (TLV) = airborne concentration for a chemical that most healthy workers can safely be exposed to for 8 hours per day repeatedly with no adverse effects. ( can be averaged over the course of the day) http: //www. tsi. com/uploaded. Images/Product_Information/Images /Small/CO-Table 1 a-new_small. jpg

ACGIH limits of exposure • TLV-STEL (short term exposure limit) = air concentration at which only 15 continuous minutes of exposure is allowed up to 4 times per 8 hour day • TLC-C (Ceiling exposure limit) = airborne values must never exceed this value.

Consequences of skin contact with a hazardous chemical • No harm • • Rashes, burns, other skin irritations Penetration of skin = allergic sensitization • Penetration of skin and entry into bloodstream resulting in systemic toxicity • Skin is normally a barrier but entry at hair follicles, sweat glands, cuts and abrasions can occur http: //www. ansellchemsafe. com/assets/content. Images/irritate 2. jp g

Toxicity by ingestion • Touching face with contaminated hands, chewing on pencils, etc. http: //cdn. womenshealthmag. com/files/images/0909 -pencilchewed. preview. jpg LD lo = lowest dose of chemical reported to cause a human death

Use of a fume hood: when is it required? Whenever using chemicals that: • Are volatile • Have unpleasant smells • Have TLV lower than 50 ppm in air http: //www. drs. illinois. edu/images/chempics/factsheets/Working. I n. AChemical. Fume. Hood. jpg

Fume hood terminology Sash: window that is impact-resistant and can be raised and lowered Baffles: direct air flow Airfoils: reduce turbulence in air flow Face velocity: rate of air flow into entrance of hood

Types of fume hoods • Fumes hoods can be “constant air volume” (changing sash height changes the face velocity) • Can also be variable air volume which means relatively constant face velocity. http: //www. expresspharmaonline. com/2009083151. jpg

Fume hood use and maintenance • Testing must occur at least annually. • Not all parts of a hood are equally good for working in. • Handle toxic chemicals 5 to 6 inches back from sash.

Fume hood rules of use • Check hood function • Put all equipment in at once, check compatibility of chemicals • Do not overload hood because blocks air flow. Keep equipment 2 inches off of hood surface • Move sash slowly and keeps hands from making sudden movements • Keep face behind hood sash • Wear face and eye protection • Do not use infectious agents (need biological safety cabinet)

Fume hood spills In the event of fire or spill: 1. Close sash completely 2. Leave exhaust fan ON 3. Unplug all equipment in hood (if outlets are outside sash) 4. Evacuate area