The following information gives an overview on environmental, health and safety aspects of Carbon Black.
Carbon Black is engineered material, primarily composed of elemental carbon. It is obtained from the partial combustion or thermal decomposition of hydrocarbons and exist as aggregates of aciniform morphology which are composed of spherical colloidal particles.
The aggregates are loosely held together by weaker forces forming larger entities called agglomerates which is the form in which Carbon Black is placed on the market. Depending on end-user industry i.e. rubber and tire or pigment industry, Carbon Black can be categorized in Rubber Blacks and Specialty Carbon Blacks, respectively.
In decades of Carbon Black production and processing using a variety of methods, no significant hazardous effects have so far been registered. Details on the individual measures regarding safe handling of Carbon Blacks are described in the relevant safety data sheets.
In end-use products, such as toners, plastics, and surface coatings, Carbon Black is matrix-bound, and according to our own surveys as well as according to neutral third party surveys, does not pose an exposure risk to end-users.
According to the National Toxicology Program (NTP/USA) as well as European (excluding Denmark) and American legislation regarding chemicals (OSHA), Rubber Blacks and Specialty Carbon Blacks do not exhibit a mutagenic, teratogenic or carcinogenic potential.
Under normal application conditions Carbon Blacks do not display any explosive potential. However, in the presence of significant igniting energy, e.g., a welding torch, Carbon Black / air mixtures may explode. For this reason, Carbon Black sources must be removed or hermetically sealed prior to equipment repairs in the vicinity of welding operations or equipment generating high operating temperatures. Carbon monoxide build-up in sealed containers is possible, such as in silos or unventilated storage facilities. Here too, ignition sources should be removed and self-contained air supply systems should be used. Carbon Blacks should be stored under dry conditions. In application or use scenarios where the general dust limit value of 10 mg / m 3 for the inhalable dust fraction and 3 mg / m 3 for the alveolar dust fraction (in Germany) or a concentration of 3.5 mg / m 3 for total dust (USA and most European countries) is exceeded, operations personnel should be required to wear a protective respirator. Spilled material can be collected to avoid dust build-up and stored in appropriate containers or burned in appropriate firing facilities.
The acute toxicity LD50 rating following oral application in rats is above 8000 mg/kg bw. Carbon Black applied on the intact skin and on the eyes of rabbits does not cause irritating or corrosive effects.
In the early 1990s, extended long-term inhalation studies with rats showed lung fibrosis and tumour development in case of lung overload with Carbon Black particles. Mouse and hamster do not develop lung tumor under similar testing conditions. Here, the significance of the animal species, the fine particle matter and the tumor triggering mechanism has not yet been determined.
In October 1995, the International Agency for Research on Cancer (IARC) reviewed the evaluation of Carbon Black and recommended an amendment to the rating of Category 3 (based on the IARC rating system). As a result, the evaluation of epidemiological data "inadequate evidence" still applies, though the overall rating was amended from Category 3 to Category 2B "possible human carcinogen" based on the long-term inhalation study made on rats under conditions of lung overload referred to above. The IARC evaluation in 2006 resulted in no changes of this rating. As a consequence of the IARC evaluation, Carbon Black is now included in the Danish cancer list and classified as a D2 A substance (poisonous and infectious material) and in the Canadian Workplace Hazardous Materials Identification System (WHMIS) under the Canadian Environmental Protection Act (CEPA). The German MAK Commission reviewed Carbon Black in 1998. The overall rating of this commission is Category 3B ("possible human carcinogen" also based on the long-term inhalation studies made on rats under conditions of lung overload.
According to the National Toxicology Program (NTP/USA) as well as European (excluding Denmark) and American legislation regarding chemicals (OSHA), Rubber Blacks and Carbon Black Pigments do not exhibit a mutagenic, teratogenic or carcinogenic potential.
Carbon black is an inorganic water insoluble substance. For this reason its bioavailability for aquatic organisms is very low. In acute tests according to OECD Test Guidelines with fish, daphnia and algae nominal Concentrations of 1000 mg / l showed no effects. Based on the physicochemical and toxicological data no chronic effects acute and no bioaccumulation are to be expected in aquatic organisms. The General Guidelines for the examination of the biodegradability of substances (OECD, EEC Guidelines) can be used only for organic substances and do not apply to Carbon Black. Carbon Black is an inert inorganic substance with the structural formula "C" and is not biodegradable by microorganisms. The German commission for the evaluation of water polluting substances has classified carbon black as a "not water endangering" substance (KBwS-No: 1742).
- McCunney RJ, Muranko HJ, Long CM, AK Hamade, Valberg PA, Morfeld P, Pattya Toxicology, Sixth Edition. Volume 5, Chapter 89, 2012
- International Carbon Black Association (ICBA) http://www.carbon-black.org
- McCunney RJ, Morfeld P, Levy L, H Muranko 2011. Carbon Black. Environ Health Perspect