Transcript Slide 1

Chapter 3: Understanding and Communicating About Laboratory Hazards
A. Section 3.1.1 Responding to Laboratory Emergencies
1.
Incident 3.1.1.1 Reusing Gloves
2.
How We Become Exposed to Hazards
a. Hazard = potential source of danger or harm (can’t eliminate)
b. Exposure = coming into direct contact with a hazard (try to minimize)
i. Route of chemical exposures: contact with skin
ii. Routes of physical hazard exposure: hit by flying particle from an explosion
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3. Routes of Chemical Exposure
a. Ingestion (Oral route): swallowing hazardous chemical
i. To be toxic, the chemical must be absorbed in the stomach or intestines
ii. Avoidance is straightforward
- Don’t Eat or Drink in the Lab
- Don’t Taste the Chemicals! (Chemists used to do this for analysis)
iii. Accidental ingestion can occur by contaminated objects (hand, pen, etc…)
Saccharin sweetener was discovered this way
b. Contact with the Eyes
i. Eyes are particularly sensitive organs exposed directly to the environment
ii. Most labs have strict safety glasses or goggles policies
iii. Spills, splashes, and broken glass are common laboratory hazards
iv. You might feel safe to take them off because of what you are doing, but you
can’t predict what your lab mates might do
v. More on Eye Protection in Chapter 7
c.
Inhalation: breathing hazardous chemical into your lungs
i. Gases can get directly into the bloodstream due to gas exchange in lungs
ii. Volatile liquids = those that easily vaporize at room temperature
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iii. Keep chemical bottles closed when not using
iv. Work with volatile liquids and toxic chemicals in a chemical fume hood
v. Homogeneous Mixtures: gaseous contaminants in (gaseous) air (same phase)
- Vapor Pressure (volatility) is correlated to boiling point
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Use the boiling point on the label to predict hazardous liquids
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vi. Heterogeneous Mixtures: solids or liquids in air (different phases)
- Colloid or Aerosol = particles from 0.01 to 100 mm
- Likely to occur when opening bottles, pouring liquids, spills
- Concentrated acids “fumes” above the liquid—open only in a hood
- Occur when grinding solids, handling fine powders, mixing solids
vii. Dangers of Aerosols
- May stay in the air for hours, contaminating you later
- Deposited in lungs, where they may react or dissolve and be absorbed
- Larger particles may end up stuck in mucous and be ingested later
viii. Avoiding Exposure
- If you can smell it, you are being contaminated
- Some chemicals smell strongly, so smelling may prevent large exposure
- Others have weak odor—the exposure may be serious before you smell
- Treat all chemicals as potential hazards, don’t wait until it stinks!
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d. Skin Exposure (dermal exposure)
i. Most common route of chemical exposure
ii. Skin is actually good at protecting us from most chemicals
iii. Some chemicals react with the skin only; others are absorbed into blood
iv. Cuts or open wounds increase the danger of exposure—keep covered
v. Spilled chemicals: small particles may expose the next user, be sure to clean
up thoroughly, especially around balances
vi. Other safety precautions: wear gloves, lab coats, absorbent covering paper,
closed toe shoes,
vii. Gloves
- Don’t have to wear them all the time
- Make sure you pick the right kind for the hazard
- More on this topic in Chapter 7
e.
Exposure by Injection
i. Some advanced chemical techniques require syringes and needles
ii. Biological labs may have to make injections
iii. Broken glass can “inject” contaminants
iv. Use extreme care when using syringes and needles
v. More on this topic in Chapter 4
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B. Section 3.1.2 Signs, Symbols, and Labels
1.
Incident 3.1.2.1 Acetic Acid Explosion
2.
Tool, Toy, or HAZARD!
a. Swimming pools, Fire, Airplanes, Cars, Medicines: Beneficial but Hazardous
b. Chemicals are similarly useful but potentially dangerous
c. Key: recognizing and respecting hazards before exposure or incidents
3.
Chemical Names—avoiding mistaken identity
a. IUPAC Nomenclature: one specific name per chemical structure
b. Common Names still (and probably always will be) used
c. CAS (Chemical Abstracts Service) Number: a specific ID # for each compound
a. CH3CH2OCH2CH3 = ether, ethyl ether, diethyl ether = CAS# 60-29-7
b. CAS # is listed on most chemical labels, often in square brackets: [60-29-7]
c. www.chemindustry.com/apps/chemicals http://webbook.nist.gov/chemistry
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4. Chemical Labels
a. OSHA requires information about hazards of every chemical be on the label
i. Law requires “Principle Hazard”
ii. Chemical may have other hazards not on the label
iii. Don’t let the Principle Hazard blind you to the other hazards!
b. Terms describing various types of hazards should be familiar to you
c. Symbols and Pictograms for various hazards are also used
Department of Transportation
(DOT) Placards for transported
materials
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5. Hazard Rating System
a. Several rating systems for various hazards exist; NFPA (National Fire Protection
Association) system is the most well-known: NFPA Diamond
b. Lab conditions ≠ Fire Conditions—some chemicals aren’t as dangerous as labeled
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C. Globally Harmonized System for Classification and Labeling of Chemicals (GHS)
1.
Incident 3.2.1.1 Isopropanol Explosion
2.
United Nations authorized GHS in 1992 to Standardize Chemical Labeling
a. Similar to United States MSDS system, but with some differences
b. Voluntary for nations to adopt and use
c. Allows global marketplace where purchaser knows what they are getting
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GHS “Purple Book” contains information on the various hazards
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Each chemical is to be accompanied by an SDS (Safety Data Sheet)
with 16 sections of hazard, handling, and disposal information.
Much like USA’s MSDS System
Federal Regulation “HazCom 2012” regulates full adoption of GHS in U.S. by 2016.
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D. Section 3.1.3 Material Safety Data Sheets
1.
Incident 3.1.3.1 Chemical Sensitivity
2.
Infinite Number of Chemicals
a. CAS had numbered over 81,000,000 compounds by 2013
b. Many have never been tested for toxicity:
a.
$100,000 per chemical using rats
b. Tiny amount ever existed in one lab
c. Chemical suppliers report what they know
d. Rules don’t require full toxicity tests
even if the chemical is bought/sold
3. Good News: most of what you encounter will
be known and toxicologically tested
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4. 1980 OSHA “Hazard Communication Standard” required Material Safety Data Sheets
a. Often called MSDS Sheets
b. Required to be supplied to all purchasers/users of sold chemicals
i. May be supplied as a paper copy (especially the first time you buy)
ii. Access to MSDS over Internet is now ubiquitous
c. Most MSDS Sheets (although not required to) follow American National Standards
Institute (ANSI) format
i. GHS follows the exact same format
for its “SDS” sheets
ii. Legally required, but may not be accurate
iii. Interesting to compare different suppliers
iv. Large chemical suppliers are generally
reliable: Sigma-Aldrich; Thermo-Fisher; etc…
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5. Using MSDS Sheets—general information
a. Primarily, you will want to find information about hazards of the compound
b. Also a good source for emergency responders as how to handle
c. Information on how to dispose of chemicals is also valuable
d. How to find Hazard Information on an MSDS
i. Match the label of the bottle to the MSDS Sheet to make sure it’s the right one
ii. Hazard information is usually found near the beginning
- “Hazard Identification”
- “Physical and Chemical Characteristics”
- “Fire and Explosion Hazard Data”
- “Reactivity and Stability Data”
- “Health Hazard Data”
- Look for: “Corrosive”, “Flammable”, “Toxic”, “Irritant”
iii. Section on Personal Protective Equipment needed for use or clean-up
- Not always specific: “Use appropriate protective gloves”
- For clean-up: “follow state and local protocols”
6. Critical Reading of MSDS Sheets
a. First source of information, but may need more specific help
b. Chemists often feels MSDS sheets overstate dangers: from NaCl MSDS sheet
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E. Section 3.2.3 Interpreting MSDS Information
1.
Incident 3.2.3.1 Isopropyl Ether Detonation
2.
Gleaning Useful Information for Hazard Assessment from MSDS Sheets
a. MSDS Sheets focus on industrial, large scale use of chemicals, not lab scale
b. Types of information on the MSDS
i. Data: simple information like mp, bp, aqueous solubility (should be correct)
One study showed >50% of 150 MSDS sheets had incorrect health
information or exposure level information
1997 report found only 11% of MSDS sheets were accurate on all four
areas studied: health effects, first aid, PPE, exposure limits
ii. Recommendations about Safety Procedures, Medical Treatment, Disposal
Useful for large industry, not the chemical lab
May not be specific enough (gloves)
May not be updated as new information is learned
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c. How MSDS Sheets are Written
i. Scientist and/or Physician may write sections
ii. Lawyers will write others: there job is to avoid liability
iii. May have been written by a computer! Generic phrases correct but not useful
d. Examples of MSDS Sheets (or their use) gone wrong
i. Banning of Styrofoam cups because “Dihydrogen Oxide” used in manufacture
ii. Recommendation to flush eyes with water if exposed to “Saline Solution”
iii. Recommendation to wear safety glasses and lab coat for deionized water
e. Don’t Dismiss Too Much
i. Sucrose (table sugar) plant: makes sense to wear goggles and dust mask
ii. Sucrose dust (like wheat dust) can explode with right ignition source
iii. Ordinary chemicals can be hazardous under the right(wrong?) conditions
3. Format of the Typical MSDS Sheet: Chemical and Hazard Identification (sect. 1-3)
a. Section 1: Chemical Product and Company Identification
i. Information: what it is and who made it
ii. Use: there for comparison to the product; contact info may be useful
b. Section 2: Composition/Information on Ingredients
i. Information: purity, CAS #, list of compounds in mixture
ii. Use: needed for an emergency or to clean up a spill correctly
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c. Section 3: Hazards Identification
i. Information: warning terms, potential health effects, exposure route
ii. Use: usually good on physical hazards, often lists so many health hazards
without specifying extent of danger that it is confusing or useless
iii. New GHS Hazard Classification: assigns appropriate relative hazard ratings
4. Emergency Measures (sect. 4-6)
a. Section 4: First Aid Measures
i. Information: general procedures if exposed, some give specific info for doctor
ii. Use: lets you develop a plan, important for doing the right first aid steps
b. Section 5: Firefighting Measures
i. Information: flammable properties, fire extinguisher, explosion hazards
ii. Use: lets you develop a plan, put out a fire, important for firefighters
c. Section 6: Accidental Release Measures
i. Information: what you should do for a spill
ii. Use: get correct spill kits, helps professional responders to a big spill
5. Managing This Hazard (sect. 7-8)
a. Section 7: Handling and Storage
i. Information: industrial intent, general warnings (no flame), incompatibles
ii. Use: usually very generic and not very helpful for a lab
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b. Section 8: Exposure Controls/Personal Protection
i. Information: ways to prevent exposure (ventilation, gloves, safety shield)
ii. Use: more useful for employer, not specific enough for lab worker
6. Hazard Recognition/Assessment Information (sect. 9-12)
a. Section 9: Physical and Chemical Properties
i. Information: just like it says
ii. Use: risk of vapor, flammability etc…; may help plan an experiment (mp)
b. Section 10: Stability and Reactivity
i. Information: conditions to avoid, incompatible chemicals, hazardous products
ii. Use: critical to someone doing reactions, helpful to emergency responders
c. Section 11: Toxicological Information
i. Information: known toxicity and human exposure limits, acute and chronic
ii. Use: lets user determine risks of using this particular chemical
iii. May not be fully tested, especially chronic (long term effects)
iv. Toxicity data changes with new data—check how old the MSDS is
d. Section 12: Ecological Information
i. Information: behavior in and effects on environment
ii. Use: informs how you will dispose of it, helpful if a spill occurs
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7. Regulated Activities (sect. 13-15)
a. Section 13: Disposal Considerations
i. Information: US EPA Resource Conservation and Recovery Act (RCRA)
requires all hazardous waste disposal be regulated; how to dispose properly
ii. Use: often very generic (follow all state and local regulations), but may mean
more to waste specialist than to you. Don’t pour stuff down the sink!
b. Section 14: Transport Information
i. Information: US Dept. Transportation regulates shipping hazardous materials,
tells about how to label and ship
ii. Use: mostly for someone shipping materials elsewhere, must follow rules
c. Section 15: Regulatory Information
i. Information: specific rules for regulated chemicals, reporting spills if too big
ii. Use: employer and EHS staff most concerned
8. Other Information (sect. 16)
i. Information: date of last revision, references, hazard ratings, disclaimers
ii. Use: hazard ratings are more specific, make sure using most recent MSDS
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F. Section 3.2.2 Information Resources about Laboratory Hazards and Safety
1.
Incident 3.2.2.1 Dimethyl Sulfate and Sodium Azide Explosion
2. Internet Resources
a. Google? Lots of misinformation (Google Scholar would be better)
b. Wikipedia? Better, but still subject to errors (user produced encyclopedia)
c. Recommendation: use reviewed material only when safety is at stake
i. MSDS Sheets can easily be found on-line
ii. They have to exist, they don’t have to be correct
iii. Table 3.2.2.1 Lists many web sites with Reviewed Safety Information
Journal of Chemical Education
Sigma-Aldrich (on-line, or the printed catalog)
Chemical and Engineering News
3. Printed Resources: a number of well-known books on laboratory hazards
Research the reaction or technique BEFORE you do it (not after a problem occurs)
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G. Section 3.3.1 Chemical Hygiene Plans
1.
2.
Incident 3.3.1.1 Hydrofluoric Acid Exposure
Planning to Succeed
a. Industrial Setting: large amounts of the same few chemicals for many years
b. Laboratory Setting: Hundreds of compounds, used intermittently or only once
c. OSHA: Employees are required by law to have a workplace free from hazards
d. Students are not covered: moral and ethical reasons (not legal) to keep them safe
e. 1990 OSH “Lab Standard” performance standard for Academic Labs
They don’t tell you how to limit exposure
They will test to see if you are and/or punish you if you aren’t (accident)
3. Chemical Hygiene Plan (CHP)
a. OSHA Requires; available to employees; How do we keep our staff/students safe
b. Chemical Hygiene Officer (CHO): responsible for the developing and
implementing the CHP (Tom Willis (recently retired), was SWOSU Dept. of Safety,
Risk Management & Workers' Compensation)
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c. Recommended CHO Duties
i. Develop CHP and appropriate measures for handling chemicals
ii. Oversee the purchase, use, and disposal of chemicals
iii. Ensure adequate safety inspections and operations
iv. Assist in incident investigation
v. Understand legal requirements
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