1. CLASSES OF CHEMICALS Toxic Chemicals Reactive Chemicals Flammables
Corrosives
Misc. (Cryogens & Compressed Gases)
Radioactive Materials

2. STRATEGY FOR HAZARD CONTROL
Hazard Recognition
Hazard Evaluation
Hazard Control
(article by Zwaard et. al.)

7. TOXIC CHEMICALS 1. DEFINITION Many classes of chemicals
Chemicals, if taken internally, disrupt or interfere with normal metabolism and are thus harmful to human body.
Many classes of chemicals

8. 2. MODES OF ENTRY INTO BODY
Inhalation –
Skin Absorption-
Ingestion-
Injection-

9. 3. TYPES OF TOXIC EFFECTS Acute Toxicity –
Causes immediate damage as result of single or short term exposure. Health problem readily apparent.
Chronic Toxicity –
Causes damage after repeated or long term exposure. Becomes evident after a long latency period.

10. 4. CLASSES OF TOXINS
Organ specific-
Carcinogens –
Mutagens-
Teratogens-
Allergens -

11. 5. FACTORS AFFECT TOXICITY
Quantity of substance-
Length of exposure-
Rate absorption into bloodstream-
Physical / chemical properties of toxin-
Nature of biological system-

12. 6. MEASUREMENT OF TOXICITY
Exposure By Inhalation
LC50 – Median Lethal Conc.
ppm or g/m3 air
Exposure By Other Routes
LD50 – Median Lethal Dose
g toxin / kg body weight

14. Safe Exposure Levels
TLV – Threshold Limit Value
- mg toxin / m3 air or ppm
a. TWA-
b. STEL-
c. C-
PEL – Permissible Exposure Level

15. 7. EXAMPLES OF TOXINS Heavy Metals – Asbestos- Organic Solvents-
Herbicides / Pesticides-

16. Formaldehyde-
a. Properties
b. Uses
c. Toxicity
d. Chronology of exposure levels

17. Phenol-
a. Properties
b. Uses
c. Toxicity
d. Problem
J. Doe weighs 190 lbs. He accidentally swallowed solution containing 5 oz. phenol. What are likely effects on J. Doe? LD50 for phenol = 530mg / kg.

18. Mercury-
a. History
b. Toxicity
c. Problem
Mercury (Hg) vapor has a TLV of 0.1mg Hg / m3 air at 250C and 1 atm total pressure. 1). Determine the vapor pressure (in mm) of mercury under these conditions. 2). Compare value to equilibrium vapor pressure of Hg (at 250C and 1 atm) which = 2 x 10-3 mm.

19. 8. PRECAUTIONARY MEASURES WHEN USING TOXINS
Proper ventilation
Make substitutes
Personal protective wear
Good hygiene practices
Avoid breakages / spills

20. 9. EMERGENCY PROCEDURES
Safety shower / eye wash
**Emergency Procedure For Spills
(be familiar with handout)
Spill Kits For Mercury