Pool chemicals in general are not safe, especially for ingestion so be sure to keep these away from small children and pets. Many of the manufacturers now make shock that will not irritate the skin so you can swim almost immediately after adding.
i think the safest chemical is oxeygen Oxygen is a very powerful mutagen but, on the other hand, it's essential to human life. Yet too little or too much and it's lethal. It's not the chemical, but the dose of the chemical.
The chemical that usually goes in a pool is chlorine. This is the first chemical as well as the last chemical to enter the water.
The hydrochloric acid is used for pool; this is a water solution of HCl.
chemical
the safest way is to whiff the smell of the liquid over to you instead of putting your nose over the chemical
bromine is a type of chemical used in a pool or hot tub to help clean the pool.
Alkalinity
called the saturation index. most good chemical test kits include it or ask your local pool store dude for it
Use litmus paper
A flashlight Answer chemical, in a sealed environment.
Use litmus paper
Sometimes when my mom and dad gives the chemical anyway the pool.