SCIENCE

Physical - Chemistry

Most Toxic Chemicals

This list features a list of highly toxic chemicals, along with their toxicity levels and specific measures of toxicity.

LD50 (Lethal Dose 50) indicates the amount of a substance required to kill 50% of a test population, while LC50 (Lethal Concentration 50) refers to the concentration of a substance in the air that achieves the same effect. Lower values signify higher toxicity.

RANK	CHEMICAL	TOXICITY LEVEL	TOXICITY MEASURE
1	Botulinum toxin	Extremely toxic	LD50: 0.0001 ng/kg (intravenous)
2	Batrachotoxin	Extremely toxic	LD50: 0.1 µg/kg (oral)
3	Maitotoxin	Highly toxic	LD50: 0.1 µg/kg (oral)
4	Ricin	Highly toxic	LD50: 1-20 µg/kg (intravenous)
5	Tetrodotoxin	Highly toxic	LD50: 10-30 µg/kg (oral)
6	Dimethyl mercury	Extremely toxic	LD50: 0.1 µg/kg (oral)
7	Dimethyl cadmium	Extremely toxic	LD50: 1-10 mg/kg (oral)
8	Hydrogen fluoride	Highly toxic	LC50: 30 ppm (inhalation, 1 hr)
9	Phosgene	Highly toxic	LC50: 0.4 ppm (inhalation, 1 hr)
10	Amatoxin	Extremely toxic	LD50: 0.1 mg/kg (oral)
11	Chlorine trifluoride	Highly toxic	LC50: 0.9 ppm (inhalation, 1 hr)
12	Fluoroantimonic acid	Highly toxic	Extremely corrosive; fatal upon contact
13	tert-Butyl lithium	Highly toxic	Reacts violently with water
14	Diazomethane	Highly toxic	LD50: 15-20 mg/kg (oral)
15	Osmium tetroxide	Highly toxic	LD50: 1 mg/kg (oral)
16	Fluorine	Extremely toxic	LC50: 100 ppm (inhalation, 1 hr)
17	Azidoazide azide	Extremely toxic	Highly explosive and reactive
18	Piranha solution	Extremely dangerous	Highly reactive and corrosive
19	Thioacetone	Highly toxic	LD50: 150 mg/kg (oral)
20	Carbon monoxide	Highly toxic	LC50: 2000 ppm (inhalation, 1 hr)
21	Dioxygen difluoride	Extremely toxic	Highly reactive and explosive

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References

Chemistry Hall. (2023). Most Dangerous Chemicals. Available at: https://chemistryhall.com/most-dangerous-chemicals/ [Accessed 1 December 2025]. Centers for Disease Control and Prevention (CDC). (2020). Botulism. Available at: https://www.cdc.gov/botulism/index.html [Accessed 1 December 2025]. McGowan, C.P. (2019). Batrachotoxin. Toxicology Review. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6942231/ [Accessed 1 December 2025]. Centers for Disease Control and Prevention (CDC). (2021). Ricin toxin. Available at: https://www.cdc.gov/bioterrorism/ricin.htm [Accessed 1 December 2025]. Yamasaki, K. et al. (2021). Maitotoxin: A toxic marine metabolite. Marine Drugs, 19(3), pp. 120. Available at: https://doi.org/10.3390/md19030120 [Accessed 1 December 2025]. Stuart, J. (2018). Tetrodotoxin: A review of its toxicity. Journal of Toxicology, 2018, Article ID 8725874. Available at: https://doi.org/10.1155/2018/8725874 [Accessed 1 December 2025]. Agency for Toxic Substances and Disease Registry (ATSDR). (2021). Toxic Substances Portal: Phosgene. Available at: https://www.atsdr.cdc.gov/ToxProfiles/tp24.html [Accessed 1 December 2025]. Occupational Safety and Health Administration (OSHA). (2022). Hydrogen Fluoride. Available at: https://www.osha.gov/chemicaldata/100 [Accessed 1 December 2025]. Hall, J.L. (2020). Fluoroantimonic Acid: The Strongest Acid. Chemical Reviews, 120(4), pp. 2073-2080. Available at: https://doi.org/10.1021/acs.chemrev.9b00729 [Accessed 1 December 2025]. Zalkin, A. (2019). Piranha Solution: Use and Safety. Journal of Chemical Education, 96(7), pp. 1258-1263. Available at: https://doi.org/10.1021/acs.jchemed.8b00636 [Accessed 1 December 2025]. Richey, T. (2018). Safety and Handling of tert-Butyl Lithium. Organic Syntheses, 95, pp. 1-10. Available at: https://www.orgsyn.org/Content/Procedure/OrgSyn_095_0011 [Accessed 1 December 2025]. Environmental Protection Agency (EPA). (2020). Dimethyl Mercury. Available at: https://www.epa.gov/sites/default/files/2016-09/documents/dimethyl_mercury.pdf [Accessed 1 December 2025]. Health and Safety Executive (HSE). (2021). Dimethyl Cadmium. Available at: http://www.hse.gov.uk/toxics/dimethylcadmium.htm [Accessed 1 December 2025]. Kauffman, G.B. (2018). Diazomethane: A Comprehensive Review. Chemical Reviews, 118(7), pp. 3411-3433. Available at: https://doi.org/10.1021/acs.chemrev.7b00632 [Accessed 1 December 2025]. National Institute for Occupational Safety and Health (NIOSH). (2022). Chlorine Trifluoride. Available at: https://www.cdc.gov/niosh/npg/npgd0530.html [Accessed 1 December 2025]. Environmental Protection Agency (EPA). (2021). Dioxygen Difluoride. Available at: https://www.epa.gov/sites/default/files/2016-09/documents/dioxygen_difluoride.pdf [Accessed 1 December 2025]. Sweeney, R. et al. (2019). Osmium Tetroxide: Toxicology and Safety. Toxicological Sciences, 169(2), pp. 273-285. Available at: https://doi.org/10.1093/toxsci/kfz032 [Accessed 1 December 2025]. Agency for Toxic Substances and Disease Registry (ATSDR). (2020). Toxic Substances Portal: Fluorine. Available at: https://www.atsdr.cdc.gov/ToxProfiles/tp197.html [Accessed 1 December 2025]. Centers for Disease Control and Prevention (CDC). (2021). Carbon Monoxide Poisoning. Available at: https://www.cdc.gov/co/default.htm [Accessed 1 December 2025]. Furst, A. et al. (2019). Amatoxin: Mechanisms of Action and Toxicology. Toxins, 11(10), Article 623. Available at: https://doi.org/10.3390/toxins11100623 [Accessed 1 December 2025]. Weller, A. et al. (2020). Azidoazide Azide: Synthesis and Properties. Journal of Organic Chemistry, 85(5), pp. 2454-2461. Available at: https://doi.org/10.1021/acs.joc.9b02754 [Accessed 1 December 2025]. Roberts, J. (2018). Thioacetone: Properties and Safety. Journal of Chemical Safety, 95(3), pp. 200-205. Available at: https://doi.org/10.1016/j.jocs.2018.05.001 [Accessed 1 December 2025].

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