Health Hazards Instructional Goal The participant will be able to interpret health hazard information for reducing personal risk when handling chemicals.

What is a health hazard?

Toxicology is the study of chemical toxicity based on epidemiological studies based on animal studies

Factors Affecting Human Response To Chemical Exposure Toxic substances Route of exposure Chemical dose Individual sensitivity Interaction with other chemicals

Forms of Toxic Substances Solids Dusts Fumes Liquids Vapors Mists

Health Hazards Asphyxiants Carcinogens Flammable Irritants Sensitizers Mutagens Teratogens Target Organ Poisons You need to understand that some chemicals may fall into more than one category.

Target Organ Poisons CNS Circulatory system Blood and blood forming system (hematoxins) Liver (hepatotoxins) Kidneys (nephrotoxins) Reproductive Organs Lungs Skin Eyes

Routes of Entry Inhalation

Routes of Entry Eye/skin (dermal contact)

Routes of Entry Ingestion

Routes of Entry Injection

Acute Response Headaches Dizziness Nausea Eye, skin or respiratory damage Unconsciousness Death

Chronic Response Frequently not reversible Liver, kidney, lung damage Target organ poisons Storage in fat (adipose) tissue

Dose - Response Relationship Dose of chemical How much / How long Response of the biological system

Dose Response Curve Dose Response LD50

(quantity vs time of exposure) Remember!! Toxic Dose (quantity vs time of exposure) The smaller the number the more toxic the dose!

Toxicity is Rate of the potential for harm from a substance Low toxicity vs. high toxicity

Toxic Concentration 500 - 5,000 mg/kg Moderately Toxic Less than 1.0 mg/kg Dangerously Toxic 1- 50 mg/kg Highly Toxic 50 - 500 mg/kg Toxic 500 - 5,000 mg/kg Moderately Toxic 5 - 50 g/kg Low Toxic

“All substances are poison ..... The right dose differentiates a poison and a remedy.”

Substance Interaction Additive 2 + 2 = 4 Synergistic 2 + 4 = 10 Potentiation 0 + 2 = 4 Antagonism 2 + 4 = 3

Toxic dose is based upon normal distribution and average health. Genetic variability is a major factor.

Less Sensitive More Sensitive Average Population

PEL/TLV,IDLH are Exposure Limits airborne concentration of a material to which nearly all individuals may be repeatedly exposed without adverse health effects. helps eliminate factor of genetic variability

Common Units for Exposure Limits ppm or ppb used with liquid, vapor, and gas mg/m3 (milligrams/cubic meter air) used with solid particulates suspended in air

Exposure Limits Permissible Exposure Limit (PEL) Threshold Limit Value (TLV) Recommended Exposure Limit (REL) Time-weighted average (TWA) Short-term Exposure Limit (STEL) Ceiling (C) Immediately Dangerous to Life or Health (IDLH)

Exposure Limits PELs - OSHA's enforceable standards TLVs - intended for use in the practice of industrial hygiene (ACGIH)

Cautions and Limitations Don’t use PELs, REls, TLVs as fine lines between safe and dangerous for evaluation or control of community air pollution for estimating the toxic potential of continuous exposure as proof of an existing disease or physical condition

Exposure Limits Time Weighted Average 8 hour day 40 hour week

TWA, STEL, C Measured Amount Exposure (ppm) TWA 8 Time (hours)

TWA, STEL, C Time (hours) Exposure (ppm) TWA STEL 4 1 2 3 4 1 2 3 Maximum of 15 minutes

TWA, STEL, C Time (hours) Exposure (ppm) TWA STEL 4 1 2 3 C

IDLH Values Concentrations of toxic substance from which escape is possible without irreversible harm should a worker's respiratory protective equipment fail.

Toxicology Protection from Toxins Know the potential for toxicity of the materials with which you work. Know the signs and symptoms of toxins effects.

Toxicology Protection from Toxins Use engineering controls. Use common sense around chemicals. Select and use protective equipment based on MSDS and safety officer recommendations. Wash exposed areas thoroughly before eating, drinking, or smoking.