Particularly Hazardous Substance

Particularly hazardous substances (PHS) are those chemicals with special acute or chronic hazards. The OSHA laboratory Standard (29 CFR § 1910.1450) defines a PHS as a select carcinogen, reproductive toxin, or substance which has a high degree of acute toxicity. The Standard requires Standard Operating Procedures (SOP) "relevant to safety and health considerations to be followed when laboratory work involves the use of hazardous chemicals." 

Two lists are provided to guide laboratories in knowing which substances require development of Standard Operating Procedures; Laboratory Chemicals and Drugs. 

PHS Lab Chemical

PHS Drug

Carcinogens - A carcinogen is a substance capable of causing cancer. Carcinogens are chronically toxic substances; that is, they cause damage after repeated or long-duration exposure, and their effects may become evident only after a long latency period. A chemical is considered a carcinogen, if it is included in any of the following carcinogen lists:

  • Under the category "known to be carcinogens" in the Annual Report of Carcinogens published by the National Toxicology Program (NTP) latest edition. These are included in the table under CARC NTP.
  • Group 1 ("carcinogenic to humans") and Group 2A (“probable human carcinogen”) of the International Agency for Research on Cancer (IARC). These are included in the table as CARC IARC.
  • OSHA-regulated carcinogens as listed in Subpart Z of the OSHA standards. These are included in the table as CARC OSHA

Reproductive Toxins - Reproductive toxins are substances capable of causing adverse effects on various aspects of reproduction, including fertility, gestation, lactation, and general reproductive performance. When a pregnant woman is exposed to a chemical, the fetus may be exposed as well because the placenta is an extremely poor barrier to chemicals. Reproductive toxins can affect both men and women. Male reproductive toxins can in some cases lead to sterility. Additional information on reproductive toxins is provided in the publication, Catalog of Teratogenic Agents, T.H. Shepard, 12th Edition, Johns Hopkins Press, 2007. These are included in the table as REPRO SHEP. 

Substances with a High Acute Toxicity - High acute toxicity refers to any chemical that falls within any of the following OSHA- defined categories: 

  • A chemical with a median lethal dose (LD50) of 50 mg or less per kg of body weight when administered orally to certain test populations.
  • A chemical with an LD50 of 200 mg less per kg of body weight when administered by continuous contact for 24 hours to certain test populations.
  • A chemical with a median lethal concentration (LC50) in air of 200 parts per million (ppm) by volume or less of gas or vapor, or 2 mg per liter or less of mist, fume, or dust, when administered to certain test populations by continuous inhalation for one hour, provided such concentration and/or condition are likely to be encountered by humans when the chemical is used in any reasonably foreseeable manner. 

These are included in the table as HTX EPA.

Drugs – Drugs included in the PHS list are those listed by the National Institute for Occupational Safety and Health (NIOSH) in Preventing Occupational Exposure to Antineoplastic and Other Hazardous Drugs in Health Care Settings (Appendix A). Hazardous drugs and the American Hospital Formulary Service (AHFS) Pharmacologic-Therapeutic Classifications are included alphabetically following the toxic chemicals discussed above.