Description/Application

  • Conté crayon is a compressed stick of pigment and clay, most commonly black, white, or sanguine (red) colored. Conté is hard and rectangular and therefore suited for drawing or sketching. 1

Resources

  • Conté contains pigment according to their color: carbon black (black), titanium dioxide (white), and iron oxide (sanguine). The clay is kaolin, which is abundant globally, and it is bound to the pigment with cellulose ether. 2, 3 Cellulose ether is a common type of binder, used as a thickener in food, industrial and various product manufacturing applications. 4 To convert plant cellulose into cellulose ether, it is treated with a corrosive solution, chloromethane, and propylene or ethylene oxide. 5

Environment

  • Kaolinite is an abundantly available mineral. However during the mining of kaolinite, up to 100 feet of earth is removed from above the deposit, which destroys ecosystems in the immediate area. 6 In Georgia, where most US kaolin is mined, the soil is replaced and the land is restored afterwards, but poorly managed mining can result in long term damage to the environment. 7

Human Health

  • During the processing of kaolinite into usable kaolin, workers are at risk of dust inhalation, which leads to lung disease. 8 The chemicals used to manufacture cellulose ether are all hazardous to human health, with exposure causing organ and reproductive damage, skin corrosion, possible nerve damage and increased risk of cancer. 9, 10, 11
  • Black conté crayon is pigmented with carbon black, which is suspected of causing cancer when inhaled as dust. 12 Students are at risk if dust from conté crayon is spread into the air, where it can be inhaled.

Social Equity        

  • Kaolinite mining and processing provides economic opportunity for thousands of residents of rural Georgia, USA. The Georgia kaolin mining industry has been noted for their excellent safety record. 7 Kaolinite mining provides employment at locations around the world. However, mining companies must prioritize the wellbeing of the surrounding community if they seek to have a long term positive impact. 13

Safe Use and Exposure

  • Take precautions to avoid inhaling dust from conté crayons, especially those containing carbon black. Clean up dust with a damp rag.

Proper disposal

  • Dispose of unusable conté crayon in the regular trash. Usable material should be donated to the givetake.

Safe Alternatives

  • Standard brands of compressed charcoal are not made with carbon black, and can be substituted for black conté.

Sources

  1. “Sketching Crayons”, Conté à Paris, http://bit.ly/2cUHPYA
  2. “Conté Sketching Crayons”, Lefranc et Bourgeois, http://bit.ly/2c87nEH
  3. “Kaolinite”, Mindat.org, http://www.mindat.org/min-2156.html
  4. “Cellulose Ethers”, Chemical Economics Handbook, http://bit.ly/2cCUXoO
  5. “Cellulose Ethers”, Dow Construction Chemicals, http://bit.ly/2cCY0gW
  6. “Prospecting and Mining”, China Clay Producer’s Association, http://bit.ly/2ctrNqF
  7. “Georgia’s Kaolin Industry Employment, Economic & Environmental Impact”, Georgia Mining Association, http://bit.ly/2cKlyw7
  8. “Kaolin dust concentrations and pneumoconiosis at a kaolin mine”, PubMed, http://bit.ly/2ctsmR0
  9. “Chloromethane”, PubChem, http://bit.ly/2ciRYm7
  10. “Propylene Oxide”, PubChem, http://bit.ly/2cTgdHh
  11. “Ethylene Oxide”, PubChem, http://bit.ly/2coFBBB
  12. “Carbon Black”, INCHEM, http://bit.ly/2cl7CrI
  13. “Needs of communities near mines in poor countries must prevail in the mining lifecycle, says Global Policy Forum”, Mining.com, http://bit.ly/2cWqroO