Practical Clues to Exposure
Odor
The odor threshold is the lowest level of a chemical that can be smelled by most people. If a chemical's odor threshold is lower than the amount that is hazardous, the chemical is said to have good warning properties. One example is ammonia. Most people can smell it at 5 ppm, below the PEL of 25 ppm. Other chemicals, like hydrogen sulfide, cause you to rapidly lose your ability to smell them (called olfactory fatigue). With these cautions in mind, knowing a chemical's odor threshold may serve only as rough guide to your exposure level. Don't depend on odor to warn you.
Taste
If you inhale or ingest a chemical, it may leave a taste in your mouth. Some chemicals have a particular taste, which may be mentioned in an SDS.
Particles in Nose or Throat
If you cough up mucous (sputum or phlegm) with particles in it, or blow your nose and see particles on your handkerchief, then you have inhaled some chemical in particle form. Unfortunately, most particles which are inhaled into the lungs are too small to see.
Settled Dust or Mist
If chemical dust or mist is in the air, it will eventually settle on work surfaces or on your skin, hair and clothing. If settled dust or mist is visible, it is possible you inhaled some of this chemical while it was in the air.
Immediate Symptoms
If you or your co-workers experience symptoms known to be caused by a chemical during or shortly after its use, you may have been over-exposed. Symptoms might include tears in your eyes, a burning sensation of skin, nose, or throat, a cough, dizziness or a headache.
Knowledge Check Choose the best answer for the question.
3-11. Which of the following is TRUE regarding a chemical's odor threshold?
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