Health hazards in the ME labs
Anca Bejan (ab4@vt.edu, 1-2509)
Environmental, Health and Safety Services
Outline
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Routes of exposure
Exposure control
Limits of exposure
Epoxy resins/systems
Fiberglass
Personal Protective Equipment selection
Respirator use at VT
Routes of exposure
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Inhalation
Ingestion
Skin/eye contact
Exposure controls
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Engineering controls (ventilation, enclosures,
substitution of material)
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Administrative controls (work practices)
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Personal Protective Equipment (eye
protection, gloves, foot protection, respirators)
Exposure limits
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Are there any “safe” limits of exposure?
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YES
Susceptibility to effects also depends on: pre-existing medical
conditions, age, gender, lifestyle choices, genetic factors,
medications, physical exertion, etc.
OSHA – enforcement (most limits are from early 1970s)
ACGIH, AIHA, NIOSH – recommended limits based on most
recent studies on animal or human health effects
Limits are set as 8 h TWA, 15 min TWA, Ceiling (ppm, mg/m3)
Excursion limits
Limits are intended to protect “nearly all workers” from adverse
health effects while working 40 h weeks for about 40 years
Health effects
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Adverse health effects
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Acute (immediate or delayed reaction)
Chronic
Nature and intensity of effects depends on:
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Intensity of exposure
Duration of exposure
Type of exposure
Health condition
Additive effect, chemical mixtures, etc
Determining contaminant concentration in air
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Personal sampling
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Pumps
Specific filters
Sampling tubes
Clorimetric tubes
Portable instruments
Determining contaminant concentration in air
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Your nose is NOT a reliable instrument
 Olfactory fatigue
 Odor treshold vs PEL, STEL, Ceiling
Acetone: 16-600 ppm (OSHA PEL: 1000 ppm ACGIH TLV: 500 ppm)
Styrene: 0.04-0.32 ppm (PEL: 100 ppm, TLV: 20 ppm)
Methylene Chloride: 25-320 ppm (PEL: 25 ppm, STEL: 125 ppm, TLV:
50 ppm)
Fiberglass: no OT; TLV: 0.1 f/cc
Epoxy systems
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Used in composite materials
Cure at room temperature
Have two parts: epoxy resin and curing agent
Epoxy resin: epichlorohydrin and bisphenol-A
Curing agent: a combination of amine
compounds
Epoxy systems
Epoxy systems- Health effects of the
components
Epichlorohydrin- skin sensitizer, URT irritant, affects male
reproductive system; known animal carcinogen
Bisphenol A- endocrine disruptor
Amines- may induce asthma and URT sensitization; some are
carcinogens
Solvents- 2 ethoxyethanol (EGEE) and 2- methoxyethanol
(EGME) affect the male reproductive system and may produce
embrio/fetal damage
Solvents- affect CNS and PNS
Epoxy use in the WARE lab
MAS Epoxies
www.masepoxies.com, look for MSDS info
MSDS
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Material Safety Data Sheet (MSDS)
Contains information about chemical composition of the product,
hazard information, first aid measures, storage, handling and PPE
requirements, fire fighting measures, accidental release measures,
etc.
Every product used in the WARE lab must have an MSDS on file
YOU MUST BE FAMILIAR WITH THE MSDSs OF THE
PRODUCTS YOU ARE USING!!!
KNOW WHERE THEY ARE LOCATED IN THE LAB AND HAVE A
COPY WITH YOU IF YOU NEED TO GO TO THE HOSPITAL
MAS- Low viscosity epoxy resin
MAS -resin
So what is the chemical composition of this resin?
- DGE-BPA (diglycidyl ether of bis-phenol A)
- Novolak - Two-step resins made by reacting epichlorohydrin with
phenol formaldehyde condensates (has more than just 2 groups of epoxy per
molecule) (http://composite.about.com/library/glossary/e/bldef-e2003.htm)
- epoxy diluents (solvents)
MAS- medium hardener
More info
Working safely with epoxy resins
A. Avoid all direct skin contact with resin, hardeners and mixed epoxy by
wearing gloves and other clothing. Clean any uncured epoxy off the skin with
waterless soap immediately after contact. NEVER use solvents to remove
epoxy from the skin. Always wash thoroughly with soap and water
immediately after contact.
B. Protect your eyes by wearing protective eye wear. If contact should occur,
flush eyes immediately with running water for 15 minutes. If discomfort
continues, seek medical attention.
C. Avoid breathing vapors. Use epoxy only in areas with good ventilation. In
small areas, be careful have a supply of fresh air and to exhaust any fumes.
Wear a respirator with an organic vapor cartridge. Wear a dust mask when
you sand the epoxy. If it has cured for less than a week, use a respirator with
the organic vapor in combination with a dust pre-filter.
D. Avoid ingestion. Wash thoroughly after each use and especially before eating
or drinking.
http://masepoxies.com/mas8.htm
Fiberglass
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Used as filler (fibers of different sizes
and composition)
Used as woven material
Fiberglass exposure
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Occurs when the fibers become airborne:
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Sanding
Polishing
Shearing/cutting
Mixing
Routes of exposure: inhalation, skin/eye contact,
ingestion
Fiberglass-health effects
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Depend on the physical dimensions and composition of the
fiber (in addition to the factors mentioned previously)
Irritation and infection of nasal mucuous membrane
Lung fibrosis
Skin irritation
Exposure control
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Use appropriate
ventilation!
Do NOT dry
sweep. Vacuum or
wet the dust
before cleaning!
Exposure control
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Always use gloves
Wear long sleeves shirts, long pants and
shoes (NO sandals)
Do NOT take contamination home!!
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Always wash hands and face before leaving
Change in “work clothes” when you are in the lab
When taking them home use a closed bag
Launder them separately
What kind of gloves?
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Very few gloves are suitable for use with all the
chemicals you might encounter in the lab
Know where to find info about the right kind of
glove (MSDS, glove manufacturer charts, etc)
Epoxy – manufacturer recommends neoprene glove
Acetone – butyl glove ONLY
Disposable latex gloves are NOT intended for
protection against chemicals and may induce
sensitization to the latex protein
Glove selection chart
Respirators
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Recommended ONLY when engineering and administrative
controls are not sufficient to minimize exposure
Last line of defense
Can be a health hazard to the user
Have several limitations that must be understood BEFORE you
decide to wear them
Do NOT fit everybody, don’t work with beards, and don’t work
at all if you are using an inappropriate filter
ALWAYS consult with EHSS before you purchase ANY dust
mask or cartridge respirator
Respirators
Where can I find more info?
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Manufacturer websites
www.osha.gov
http://www.atsdr.cdc.gov/
http://www.cdc.gov/niosh/homepage.html
http://www.iarc.fr/
http://www.bestglove.com/
http://www.ansell.com
VT EHSS : www.ehss.vt.edu