Some chemicals react on the skin surface, causing dermatitis. Symptoms range from simple reddening, drying and itching associated with some detergents to blistering or severe burns from strong corrosives. Protective equipment such as gloves, lab coats, aprons, safety glasses, and face shields are the best ways to avoid skin contact with chemicals. Small amounts of contamination that may not affect the rough skin of the hands can cause irritation if transferred to more sensitive areas such as lips, eyes or genital areas. Therefore, wash hands before applying cosmetics or using the bathroom.
Inhalation is the third route of entry.
This is the most difficult exposure to control because we must breathe the air around us. Adverse health effects from inhaled contaminants range from respiratory irritation to pulmonary and systemic disease. However, laboratory exposures seldom are of sufficient concentration or duration to result in such outcomes. When a health risk does exist, local exhaust systems, such as the chemical fume hood, provide protection. All three must be controlled to prevent adverse health effects.