How Do You Make Decisions About Exposure?
How toxic is the material?
A TLV® (Threshold Limit Value) is defined as a guideline designed for use by industrial hygienists in making decisions regarding safe levels of exposure to various chemical substances and physical agents found in the workplace. TLVs® are health-based values established by scientists that review existing published and peer-reviewed literature in various scientific disciplines (e.g., industrial hygiene, toxicology, occupational medicine, and epidemiology) to make a decision. TLVs® are published by the American Conference of Governmental Industrial Hygienists (ACGIH).
What is the toxic action of the material? Toxic fibers, chemicals and metals have different reactions:
Other things to consider:
Depending upon what you are doing and how you are doing it, exposure levels are variable.
What is the route of exposure?
You need to understand the potential effects of the chemical:
Possible routes of exposure:
There are exposure limits for many chemicals:
OELs - Occupation Exposure Limits:
Time Weighted Average example:
Rarely is exposure consistent throughout the day. Let's say you are working in your studio for 8 hours grinding glass and exposure varies throughout the day. The OEL = 10 mg/m3 and the Time Weighted Average - 3.2 mg/m3. Actual exposure is below OEL:
More LEAD resources on the Internet:
More information: Clean Washington Center
A MSDS will provide you with information about the product:
Where to find MSDS's on the Internet:
Replace toxic with less toxic
Ventilate the area - fans, point source ventilation
Wet Methods to control dust
Personal Protective Equipment:
Respirators, ear plugs, gloves
Spread the exposure out over time
Bullseye Frit comes in a variety of sizes:
Powder (0.2 mm and finer)
Fine (0.2 - 1.2 mm)
Medium (1.2 - 2.7 mm)
Course (2.7 - 5.2 mm)
Only powder is possibly respirable! Fine is considered “inhalable” but is too large to be of real pulmonary consideration.
But I must agree with the industrial hygienist Greg Rawls that the glass dust, while no picnic for the lungs, does not cause silicosis. But remember, these people's illness is related to exposures they probably had 10, 20 or more years ago. Back then, studios did abrasive blasting with real silica sand, whiting was ground marble and highly contaminated with free silica, kiln wash often contained powdered silica, etc. There was plenty of silica around back then--and even now--if you are not savvy about the composition of the materials you use.
Monona Rossol, M.S., M.F.A.
President of ACTS, Safety Director, United Scenic Artists, Local 829, IATSE
How do you determine if a material is toxic?
Epidemiology studies: Study the past/future effects of exposures on humans. This is the best indication of toxicology.
Animal Studies: Exposure lab animal to a material under controlled circumstances. Fair to good indication of toxicology depending upon the test methodology. LD50 (ingested lethal dose, 50% population), LC50 (inhaled lethal concentration, 50% population).
Petri Dish Studies: Determine possible chemical mutagenicity in bacteria. Starting point that indicates further investigation is needed.
How reliable is toxicity data?
Depends upon the results of the study. Is it “Good Science”?
Relative Risk: Probability of outcome. Relative risk is simply the ratio of the two conditional probabilities. A relative risk equal to 1 implies that the the event is equally probable in both groups. A relative risk greater than 1 implies that the event is more likely in the first group. A relative risk less than 1 implies that the event is less likely in the first group.
Always read the MSDS for any material used. Sometimes silica is a component of other products.
There are a variety of materials you can use for sandblasting:
Kiln Wash (Bullseye)
Thin Fire Paper (Bullseye)
Glass Artists use a variety of chemicals that can be harmful. Always know the toxicity of chemicals and materials you work with.
Best source of information about a chemical is the MSDS:
Women who are pregnant or nursing should consult with their OB/GYM prior to kiln working!
In reality, unless you are doing:
You are not really at risk for an unacceptable exposure when working in a glass studio
HEALTH & SAFETY - CHEMICALS
Refractory Ceramic Fibers
TLV: 0.2 fibers/cubic centimeter (8 hour TWA) - This is very low and indicates high toxicity
Does glass firing in a kiln let off toxic fumes?
What about glass and Food Safety?
WORKS OF ART IN KILN-FORMED GLASS