KCl

Potassium chloride is also commonly known as “Muriate of Potash”
used in medicine, scientific applications, and judicial execution through lethal injection. The majority of the potassium chloride produced is used for making fertilizer. Side effects can include gastrointestinal discomfort including nausea and vomiting, diarrhea and bleeding of the gut. Orally it is toxic in excess, high doses can cause cardiac arrest and rapid death.
http://en.wikipedia.org/wiki/Potassium_chloride

FDA pregnancy category C. This medication may be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment. It is not known whether potassium chloride passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.
http://www.drugs.com/potassium_chloride.html

Symptoms of a potassium chloride overdose may include paralysis, numbness or tingly feeling, uneven heartbeat, feeling light-headed, fainting, chest pain or heavy feeling, pain spreading to the arm or shoulder, nausea, sweating, seizure (convulsions), or coma.
http://www.drugs.com/potassium_chloride.html

side-effects of potassium chloride:

  • chest pain or heavy feeling, pain spreading to the arm or shoulder, nausea, sweating, general ill feeling;
  • uneven heartbeat
  • confusion
  • unusual tiredness, weakness, or heavy feeling
  • stomach pain or severe cramping or black, bloody, or tarry stools.

http://www.drugs.com/potassium_chloride.html

Hazards
Emergency Overview: CAUTION! MAY BE HARMFUL IF SWALLOWED. MAY CAUSE IRRITATION TO SKIN, EYES, AND RESPIRATORY TRACT.
http://www.jtbaker.com/msds/englishhtml/P5631.htm

Potential Health Effects
Inhalation:
Inhalation of high concentrations of dust may cause nasal or lung irritation.
Ingestion:
Large quantities can produce gastrointestinal irritation and vomiting. May produce weakness and circulatory problems. May affect heart. In severe cases, ingestion may be fatal.
Skin Contact:
Contact may cause irritation or rash, particularly with moist skin.
Eye Contact:
Potassium chloride is moderate eye irritant. Redness, tearing, possible abrasion can occur.
Aggravation of Pre-existing Conditions:
Persons with impaired kidney function may be more susceptible to the effects of the substance.