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In the United States, expert advice from a regional poison control center may be obtained by calling 1-800-222-1222. If cyanide poisoning is suspected, emergency medical personnel should be contacted immediately (dial 911).

How Toxic Is Cyanide | CYANIDE INSIGHT
Potential cyanide exposure may be caused by the combustion of many household items. See how quickly hydrogen cyanide (HCH) may become toxic and deadly.

How Toxic is Cyanide When Inhaled?

In a fire smoke emergency, potential cyanide exposure can be caused by the combustion of many household items.6 This combustion creates hydrogen cyanide (HCN), which can quickly rise to dangerous levels in small spaces.1

Poisoning caused by cyanide depends on the amount of cyanide a person is exposed to, the route of exposure, and the length of time that person is exposed.

On the chart below, drag the gauge to see how quickly HCN can become deadly based on concentration levels in the atmosphere.


25 PPM

  • 18-36 PPM
  • 45-54 PPM
  • 110-135 PPM
  • 135 PPM
  • 181 PPM
  • 270 PPM

Slight symptoms after several hours

Can be tolerated for 30-60 minutes

Fatal after 30-60 minutes or longer

Fatal after 30 minutes

Fatal after 10 minutes

Immediately fatal

PPM or Parts Per Million= This is a way of expressing very diluted concentrations of substances in the atmosphere. Just as percent means 'out of a hundred', so parts per million (ppm) means 'out of a million'.

Did you know?

Hydrogen cyanide (HCN) can be
35 times more toxic than carbon
monoxide (CO).7