What are chemical contaminants? 1)Homemade soaps.
2)Restaurant grade cleaners.
3)Alcohol.
4)Recreational drugs.

Chemical contaminants are chemicals toxic to plants and animals in waterways. The phrase 'chemical contamination' is used to indicate situations where chemicals are either present where they shouldn't be, or are at higher concentrations than they would naturally have occurred.

when in a crucial situation, after calling 911, the correct posture for delivering effective compression is the proper hand placement.

first, place two fingers at the sternum, then put the heel of your other hand next to the fingers and place hand on top of the other. lock your elbows by using your body’s weight and compress the victim’s chest with a depth of 2 inches.

moreover, do 15 compression and 2 breaths, this process must be done four times until there is a pulse or a arrive.