What two things are necessary to prove an exposure occurred?

Two Things that are necessary to prove an exposure has occurred are the following;

·         Changes in the surrounding such as the smell, sight or feeling. An example is when there is a presence of broken bottles that has a content of hazardous chemical and that there is a presence of strong scent.

·         Another thing observance of a leak or broken bottles or containers that contains with potential harmful pathogens, this should be reported right away because this can lead to serious consequences.