Editing Carbon (section)

==Precautions==
[[File:Worker at carbon black plant2.jpg|thumb|left|upright|Worker at [[carbon black]] plant in [[Sunray, Texas]] (photo by [[John Vachon]], 1942)]]
[[File:Centrilobular emphysema 865 lores.jpg|thumb|upright=1.3|Gross pathology of lung showing centrilobular emphysema characteristic of smoking. Closeup of fixed, cut surface shows multiple cavities lined by heavy black carbon deposits.]]

Pure carbon has extremely low toxicity to humans and can be handled safely in the form of graphite or charcoal. It is resistant to dissolution or chemical attack, even in the acidic contents of the digestive tract. Consequently, once it enters into the body's tissues it is likely to remain there indefinitely. Carbon black was probably one of the first pigments to be used for tattooing, and [[Ötzi the Iceman]] was found to have carbon tattoos that survived during his life and for 5200&nbsp;years after his death.<ref>{{cite journal |first1=Leopold |last1=Dorfer |date=1998 |title=5200-year old acupuncture in Central Europe? |journal=Science |volume=282 |pages=242–243 |doi=10.1126/science.282.5387.239f |pmid=9841386 |last2=Moser |first2=M. |last3=Spindler |first3=K. |last4=Bahr |first4=F. |last5=Egarter-Vigl |first5=E. |last6=Dohr |first6=G. |issue=5387 |bibcode=1998Sci...282..239D |s2cid=42284618}}</ref> Inhalation of coal dust or soot (carbon black) in large quantities can be dangerous, irritating lung tissues and causing the congestive lung disease, [[coalworker's pneumoconiosis]]. Diamond dust used as an abrasive can be harmful if ingested or inhaled. Microparticles of carbon are produced in diesel engine exhaust fumes, and may accumulate in the lungs.<ref>{{cite journal |last1=Donaldson |first1=K. |date=2001 |title=Ultrafine particles |journal=Occupational and Environmental Medicine |volume=58 |pages=211–216 |doi=10.1136/oem.58.3.211 |pmid=11171936 |last2=Stone |first2=V. |last3=Clouter |first3=A. |last4=Renwick |first4=L. |last5=MacNee |first5=W. |issue=3 |pmc=1740105}}</ref> In these examples, the harm may result from contaminants (e.g., organic chemicals, heavy metals) rather than from the carbon itself.

Carbon generally has low toxicity to life on Earth; but carbon nanoparticles are deadly to ''[[Drosophila]]''.<ref>[https://www.sciencedaily.com/releases/2009/08/090807103921.htm Carbon Nanoparticles Toxic To Adult Fruit Flies But Benign To Young] {{webarchive|url=https://web.archive.org/web/20111102130334/https://www.sciencedaily.com/releases/2009/08/090807103921.htm |date=2011-11-02}} ScienceDaily (Aug. 17, 2009)</ref>

Carbon may burn vigorously and brightly in the presence of air at high temperatures. Large accumulations of coal, which have remained inert for hundreds of millions of years in the absence of oxygen, may [[spontaneously combust]] when exposed to air in coal mine waste tips, ship cargo holds and coal bunkers,<ref>{{cite web |url=https://www.geosociety.org/news/pr/04-30.htm |title=Press Release – Titanic Disaster: New Theory Fingers Coal Fire |website=www.geosociety.org |access-date=2016-04-06 |url-status=live |archive-url=https://web.archive.org/web/20160414183351/http://geosociety.org/news/pr/04-30.htm |archive-date=2016-04-14}}</ref><ref>{{cite web |url=http://www.spanamwar.com/mainecoal.html |title=Coal bunker Fire |last=McSherry |first=Patrick |website=www.spanamwar.com |access-date=2016-04-06 |url-status=live |archive-url=https://web.archive.org/web/20160323134109/http://www.spanamwar.com/mainecoal.html |archive-date=2016-03-23}}</ref> and storage dumps.

In nuclear applications where graphite is used as a [[neutron moderator]], accumulation of [[Wigner energy]] followed by a sudden, spontaneous release may occur. [[Annealing (metallurgy)|Annealing]] to at least 250&nbsp;°C can release the energy safely, although in the [[Windscale fire]] the procedure went wrong, causing other reactor materials to combust.

The great variety of carbon compounds include such lethal poisons as [[tetrodotoxin]], the [[lectin]] [[ricin]] from seeds of the [[castor oil plant]] ''[[Ricinus communis]]'', [[cyanide]] (CN{{sup|−}}), and carbon monoxide; and such essentials to life as glucose and protein.