Chapter 25: TOXICOLOGY

1
Chapter 25 TOXICOLOGY

• Deals with the long term effects of foreign
  chemicals on the body
• Depends on type and amount, that can be either
  critical or cumulative (like CTDs)
• May be a long lag between exposure and response
  (e.g. asbestos)

2
Poisons

• Effects often tested on animals
• Threshold Limit Values (TLVs) help determine
  whether effects are reversible or not
• TLVs are directly proportional to body mass

3
Poison Delivery Routes
SKIN Natural barrier is compromised with open
cuts / abrasions MOUTH Forbid eating / drinking
/ smoking in a work area to avoid
ingestion LUNGS Particle size determines what
is inhaled, retained. Small particles are more
dangerous.
4
Toxicology Controls
Can be via engineering, administrative or
personal protection methods Table 25.2
5
Toxicology Controls

• Substitute a less harmful material
• Use water base instead of organic base cleaning
  compounds.
• Some substances are much more volatile than
  others and in most situations its best avoided.
• Change the material or process
• Use safety cans instead of glass bottles
• Use vacuum cleaner instead of compressed air for
  blowing particles
• Wear safety glasses in operations that might be
  harmful to eyes

6
Toxicology Controls

• Enclose (Isolate) the process
• Capture vapors before they disperse out
• Have sophisticated processes for gluing, painting
• Use Wet Methods
• Use high pressure water jet instead of abrasive
  blasting for cleaning operations
• Use moistened flint in pottery

7
Toxicology Controls

• Provide local ventilation
• In work area, general sequence should be input
  air, worker, contamination and then exhaust air.
• Dont allow fumes to travel inside the work place
• Allow local ducts
• Provide general (dilution) ventilation
• When the contaminant is released from a non-point
  source, use general ventilation
• Forced ventilation is preferred over natural due
  to speed and directional controls

8
Toxicology Controls

• Use Good House Keeping
• Remove dust from floor
• Eliminate piles of open containers of chemicals
• Immediately clean up the spills
• Control Waste Disposal
• Should have safe waste disposal
• Separate hazardous with non hazardous waste
• Storage area should be fail-safe

9
Toxicology Controls

• Screen Potential Employees
• Avoid using workers who are hypersensitive to a
  particular
• substance
• Screening out cigarette smokers from exposure to
  asbestos
• Periodically examine employees
• Train the supervisors, engineers, and workers
• Reduce exposure time

10
Toxicology Controls

• Personal Protection
• May involve completely sealed body suit and hood,
  or just a face mask and gloves
• If the clothing is saturated, throw it away
• Run an empty cycle with hot water and detergent
  before using the washer again.