The eyes may also be a route of entry. Usually, however, only very small quantities of chemicals in the workplace enter through the mouth or the eyes. Regardless of the way the chemical gets into the body, once it is in the body it is distributed to anywhere in the body by the blood stream. In this way, the chemicals can attack and harm organs which are far away from the original point of entry as well as where they entered the body. Contaminated air in the workplace can be inhaled.
Air is drawn through the mouth and nose and then into the lungs.
An average person will breath in and out about 12 times a minute. Each of the 12 inhalations brings in about 500 mL of air, corresponding to 6 litres of air per minute, together with any contaminants that the air contains. People involved in hard physical work will breathe harder and take in more than 6 litres a minute. Over an 8-hour working day, more than 2,800 litres of air will be breathed in and out of the lungs. In conditions of hard physical work, up to 10,000 litres may be exchanged.