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Top 20 Hazardous Substances

The list below contains the Top 20 hazardous substances, in terms of threats to human health. The list was compiled by the Agency for Toxic Substances and Disease Registry (ATSDR) / US Public Health Service / US Department of Health and Human Services and the US Environmental Protection Agency.

  1. Arsenic
  2. Lead
  3. Mercury
  4. Vinyl Chloride
  5. Polychlorinated Biphenyls (PCBs)
  6. Benzene
  7. Cadmium
  8. Benzo(a)pyrene
  9. Polycyclic Aromatic Hydrocarbons (PAHs)
  10. Benzo(b)fluoranthene
  11. Chloroform
  12. DDT, P'P'
  13. Aroclor 1254
  14. Aroclor 1260
  15. Trichloroethylene
  16. Dibenz[a,h]anthracene
  17. Dieldrin
  18. Chromium (+6)
  19. Chlordane

Arsenic (CAS# 7440-38-2)

Lead (CAS# 7439-92-1)

Mercury (CAS# 7439-97-6)

Vinyl Chloride (CAS# 75-01-4)

Polychlorinated Biphenyls (PCBs) (CAS# 1336-36-3)

Benzene (CAS# 71-43-2)

Cadmium (CAS# 7440-43-9)

Benzo(a)pyrene (CAS# 50-32-8)

Polycyclic Aromatic Hydrocarbons (PAHs) (CAS# 130498-29-2)

Benzo(b)fluoranthene (CAS # 205-99-2)

Chloroform (CAS# 67-66-3)

DDT, P'P'- (DDT, DDD)
DDT (CAS#s 50-29-3)

DDD (CAS# 72-54-8)

Aroclor 1254 (11097-69-1)

Aroclor 1260 (11096-82-5)

Trichloroethylene (TCE) (CAS# 79-01-6)

Dibenz[a,h]anthracene (CAS# 53-70-3)

Dieldrin (Dieldrin / Aldrin)
Dieldrin (CAS# 60-57-1)

Chromium (+6) (CAS# 7440-47-3)

Aldrin (CAS# 309-00-2)

Chlordane (CAS# 87-68-3)

Hexachlorobutadiene (CAS# 87-68-3)

The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) requires that ATSDR and US EPA prepare a list (in order of priority), of substances that are most commonly found at sites on the National Priorities List (NPL), which pose a significant potential threat to human health due to their toxicity and potential for human exposure at these NPL sites. For further information on the evaluation process and the complete set of 275 substances, access the Priority List of Hazardous Substances.