Safety in the Laboratory

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Safety Data Sheets
Background
Safety in the lab starts with preparation. You have already covered safety guidelines on how to
dress, behave, and approach certain problems that arise in the laboratory. However, truly being
prepared means also understanding how to handle each individual chemical before utilizing it in
an experiment. To learn the basic health hazards and safety equipment needed when handling a
substance we turn to the Safety Data Sheet, or SDS (formerly Material Safety Data Sheet,
MSDS). An SDS outlines the specific information a scientist or medical profession needs to
know about handling a substance and/or treating an overexposure to substance. The SDS will
inform a user if gloves, apron, goggles, or facemask should be worn while using the reagent. It
will also inform the user what to do in case of contact with skin or eyes, or if vapors are inhaled.
The sections of an SDS sheet are as follows:
1. Compound Identification
a. Compound name
b. Production company
c. CAS (Chemical Abstract
System) number which is a
unique identifier of a
substance
d. Possible common names
i. A great example of
this is sucrose, also
known as table sugar.
2. Compound Hazards
a. Effects
i. Acute: short-term or
one-time exposure to
a substance
ii. Chronic: long-term
exposure
3. Composition/Ingredient Information
a. Synonyms for naming
b. Chemical formula
c. Molecular weight
d. Hazardous components
4. First Aid
a. Effects may also appear in
this section.
5. Firefighting
6. Accidental Release Measures
7. Handling and Storage
8. Personal Protection
9. Physical and Chemical Properties
10. Stability and Reactivity
11. Toxicology
a. Lethal dosage levels
(explained later)
b. Effects may also appear in
this section.
12. Ecological Information
13. Disposal
14. Transportation
15. Regulatory
16. Other
a. National Fire Protection
Association Ratings
(explained later); Hazmat
Diamond
Consider section 11-a. To help the user understand what level of exposure is considered harmful,
the SDS will also provide information on different exposure level guidelines and a lethal dosage
level (LD50) or lethal concentration (LC50) rating. This is a term used to help a user gauge the
toxicity of the compound or solution he/she is utilizing. The LD50 level informs the user what
level of exposure is considered lethal to 50% of a population, while the LC50 level tells the user
at what concentration a substance is lethal if in the air or in solution. While lethal dosage testing
is no longer carried out in the format of LD50 and LC50 testing due to concerns for animal
cruelty, the values are still shown in SDS sheets as a way to help individuals understand the
toxicity of a substance.
Created by Erin O’Connell
Let us use caffeine as an example. In rats the LD50 for caffeine is considered 192 mg/kg of body
weight. The average brown rat weighs approximately 0.300 kg. This means that if you studied a
group of brown rats at the average rate 57.5 mg of caffeine would be lethal to 50% of the
population. The average cup of coffee contains 91 mg of caffeine in an 8 oz cup. In other words,
if you have a pet brown rat, do not let it drink your coffee! Levels far below that would cause
health concerns for your pet.
But what about people? Let us consider caffeine again, but for humans. The LD50 level for
humans is based on individual health and sensitivities, but ranges between 150-200 mg/kg of
body weight. The average adult human weighs 62 kg (137 lbs). This means that the average
human can consume between 9300-12400 mg of caffeine. That is 102 – 136 cups of coffee!
An example of “Other” information the SDS provides that is helpful is The National Fire
Protection Association (NFPA) rating. The NFPA requires that all chemicals contain an NFPA
rating on a label and for all storage areas. The NFPA rating is found in the form of a quad color
diamond known as the Hazmat Diamond (Figure 1) on a chemical container or storage room
label, and in the “Other” section on the SDS form. The four colors of the diamond indicate
hazards for health (blue), flammability (red), reactivity (yellow), and specialty hazards (white).
The levels of hazard range from 0 (none) – 4 (Extreme), and may be seen in Figure 1 below.
Figure 1: NFPA Label Guide
Figure 2: NFPA Label of Acetic Anhydride
An example of an NFPA label may be seen in Figure 2. This label tells us that acetic anhydride has
serious health implications (serious or permanent injury upon exposure), is somewhat flammable
(high ambient temperatures), is somewhat instable (at high temperatures), and is corrosive. We can
see that many manufacturers also list suggested safety equipment images to go along with the label.
This way a user has a general understanding of proper safety precautions and safety concerns.
The trick to SDS sheets is to use reasoning and your critical thinking skills! Often times the sheets
will use warnings that are stock phrases. For example sucrose (table sugar) tells you in the SDS that if
it is swallowed the person should “induce vomiting” and “contact a physician”. Sucrose is generally
not toxic, accept at very high concentrations (29700 mg/kg in a rat). Humans consume sucrose all the
time, safely. No doctor would suggest you induce vomiting for eating a food because it contains
sugar.
Created by Erin O’Connell
Name: _________________________
Safety Data Sheet
Using the SDS provided for Aspirin, answer the following questions.
1. List the CAS number for aspirin.
2. What is the chemical name, listed as the synonym, for aspirin?
3. What is the LD50 level for aspirin in rabbits?
4. What does the SDS suggest as protocol if aspirin comes in contact with your skin? If it is
ingested?
5. Does the protocol you listed in step 4 seem reasonable? Why or why not?
6. Using the NFPA label (Hazmat diamond) below, fill in the appropriate hazard numbers, and
mark the appropriate protective gear required.
Required Personal Protection Equipment
Created by Erin O’Connell
Safety Glasses
Gloves
Splash Goggles
Synthetic Apron
Face Shield
Full Suit
Dust Respirator
Boots
Vapor Respirator
Other: _____________
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