Uploaded by Jeralyn Juarez

Safety College Lab

• Recognize hazards
• Assess the risks of the hazards
• Minimize the risks
• Prepare for emergencies
Types of hazards
• Physical hazards
• Chemical hazards
• Health hazards
• Reactive hazards
Physical Hazards
• Electricity
• Compressed gases
• Heat: Hot plates, ovens
• Cold: Liquid N2, dry ice
• Radiation: X-rays
• Asphyxiation: N2, Ar, He
Special chemical hazards every chemist
should know
Powerful acids: HCl(aq), HNO3, H2SO4, concentrated acetic acid
Powerful bases: NaOH, KOH, NH3(aq)
Powerful oxidizers: perchloric acid, O2, nitrates, Br2
Flammable liquids, esp. organic solvents
Poisonous gases: HCN, Zn fumes, H2, NH3, Cl2, HCl(g), NO2
Peroxides, esp. in ethers
Cyanides with acids
Heavy metals, esp. mercury
Radioactive materials
Pyrophoric materials, esp. Na & K
Explosive powders: sugar, wheat, Al, Mg
Hg compounds, esp. organic mercury compounds
• What is fire?
• The fire triangle
• Types of fires and their extinguishers: A, B, C, D
Fire is rapid oxidation of a fuel, with emission of light and heat.
The fire triangle
Fuel: Hydrocarbons, H2, NH3, metal powder, wood, NH4NO3, etc.
Oxidizer: Air, O2, F2, N2O, NaNO3, NH4NO3, H2O2
Ignition: Spark, flame, UV light, friction
Hypergolic materials ignite on contact—no ignition.
Types of fires and extinguishers
• Extinguish or evacuate?
• Policy at York is to discourage extinguishing, even
though we are required to have fire extinguishers.
• Before evacuating, notify relevant people (instructor or
Public Safety at York)
Health Hazards
• Acute (brief) exposure: mainly strong reagents
• Chronic (long term) exposure: mainly weak reagents
Reaction Hazards
• Incompatible chemicals
Don’t store acids with bases
Don’t store oxidizers with reducers
Don’t store acids with cyanides
• Catalysts: Runaway reactions
• Explosives
• Pyrophoric chemicals
NFPA Diamond
High numbers are worse!
Globally Harmonized System (GHS)
GHS language includes:
• A signal word (such as “danger” or “warning”)
• A symbol or pictogram (such as a flame within a red-bordered
• A hazard statement (such as “causes serious eye damage”)
• Precautionary statements for safely using the chemical
17 physical hazard classes
10 health hazard classes
2 environmental hazard classes
Low numbers are worse!
Safety Data Sheets (SDS)
Safety Data Sheets (SDS)
Used to be called Material Safety Data Sheet (MSDS)
Legal and technical content
More recent versions are generally more useful
Available for anything you buy
Format is specified, but content is not; every company can
generate its own
• Must be made available to all employees in a print copy
Safety Data Sheets (SDS)
Examine sucrose SDS.
Chemtrec = company with hazmat incident response phone number
CAS number
ACGIH = American Conference of Governmental Industrial Hygienists
TWA = time-weighted average
PEL = permitted exposure limit
LD50 = dose lethal to 50% of population
IARC = International Agency for Research on Cancer
NTP = National Toxicology Program
OSHA = Federal Occupational Safety and Health Administration
Minimize Risks
Air turnover in the lab should be 6 air changes per hour.
Supply air intake should be far from all exhausts.
Put stuff as far to the back as you can manage,
and don’t block the air flow.
Personal protective equipment
• Gloves
• Eye protection: goggles, safety glasses, contact lenses,
prescription glasses
• Lab coats and aprons
• Face masks (respirators), face shields for splashes and heat
Mill gloves for handling hot
glassware and crucibles, or dry ice
Respirators and face masks
Face shield
Furnace face shield. The
thin gold coating reflects IR.
• Fire
• Electrical shock
• Burns from contact with hot objects
• Chemical burns
• Cuts
• Strong reagent spills
Electrical Shock
Current determines damage, not voltage.
Usually, anything above 0.1 A is dangerous. Houses are typically wired for 200 A, labs for more. You can feel as little
as 1 mA.
For a constant voltage, the current is determined by resistance. Air and dirt are good insulators. Water and metal
are good conductors.
Circuit breakers and fuses break a circuit if the current goes above a limit. The limit is usually far above fatality.
These devices prevent property damage and fires. They don’t protect people.
Current causes muscle contraction, making it hard to let go. Involuntary screaming.
Do not touch a person being shocked—turn off the power!
What is waste? When it leaves the experimental setup
Waste consolidated from several labs; pick-up by special contractors; how do they dispose of it?
Separation of waste to reduce interactions (chemical reactions) among the waste, and sometimes to make money
Read labels and use your chemistry knowledge to make good choices. Don’t mix acids with bases, oxidizers with
reducers, cyanides with acids, etc.
Other resources: