Environmental and health implications of carbon (7440440) and graphite (7782425) fibers are reviewed. These fibers are made commercially from any carbonaceous, fibrous raw material that pyrolyzes to a char and leaves a high carbon residue. Carbon fibers are pyrolyzed at 1200 degrees-C and consist of amorphous carbon; graphite fibers are carbon fibers that have been heat treated to temperatures of 200 to 2700 degrees, resulting in a crystalline fiber structure. NASA tests of carbon and graphite fibers released during simulated aircraft burns are summarized. A small percentage of fibers with diameters less than 3.5 micrometers (microm) and length greater than 10microm were released. Concentrations were on the order of 0.1 fibers per cubic centimeter. Animal toxicity studies in which guinea-pigs were exposed to airborne carbon fibers indicated the presence of fibers 10microm in diameter and 100microm in length or 1.0 to 2.5microm in diameter and less than 15microm in length in the lungs. No tumors were found. The authors recommend that well designed animal toxicity studies be performed with carbon and graphite fibers on the order of 3.5microm in diameter or less and 10microm in length.
We take your privacy seriously. You can review and change the way we collect information below.
These cookies allow us to count visits and traffic sources so we can measure and improve the performance of our site. They help us to know which pages are the most and least popular and see how visitors move around the site. All information these cookies collect is aggregated and therefore anonymous. If you do not allow these cookies we will not know when you have visited our site, and will not be able to monitor its performance.
Cookies used to make website functionality more relevant to you. These cookies perform functions like remembering presentation options or choices and, in some cases, delivery of web content that based on self-identified area of interests.
Cookies used to track the effectiveness of CDC public health campaigns through clickthrough data.
Cookies used to enable you to share pages and content that you find interesting on CDC.gov through third party social networking and other websites. These cookies may also be used for advertising purposes by these third parties.