Chemical Safety Lecture Notes PDF

# UNIT I: Chemical Safety ## I. INTRODUCTION The chemical materials are extremely hazardous, therefore we have to learn how to deal with this hazardous materials and how to decrease the characteristics hazards when we use them. The industrial companies for chemical compounds provide the customers...

# UNIT I: Chemical Safety ## I. INTRODUCTION The chemical materials are extremely hazardous, therefore we have to learn how to deal with this hazardous materials and how to decrease the characteristics hazards when we use them. The industrial companies for chemical compounds provide the customers with total information for each chemical compound, these information are labeled or are given separately as MSDS which is called safety data sheet. Each one in the chemical laboratories is responsible to keep the safety, therefore the supervisor of the chemical lab must learn, the teachers which are must learn the students or any one interest in the lab, about the principal safety behaviors in the chemical labs. Therefore, before any chemical experiment you have to know everything about the chemicals that are involved in the experiment, the nature of the reaction and the nature of the product, also you have to know if the product produced is toxic or not and how to clean the containers and glassware. ## II. Routes of Entry Toxic chemical compounds may enter the body in four ways, called “routes of exposure” or “routes of entry”. The first entry route which will be illustrated is inhalation. ### 1. Inhalation Inhalation is the most common route of entry for chemicals into the body. The vapors or fumes released from chemical containers or during the chemical reaction being carried out can enter the respiratory system if adequate precautions are not taken. The impact on the respiratory system will depend upon the type of chemical, its properties, concentration of the chemical and duration of exposure. The chemical vapors can cause severe irritation of the respiratory tract or it can be absorbed into the blood stream to be carried to target organs. The respiratory system has its own defense mechanism against foreign materials entering it. The mucous secretion along the nasal cavity and millions of tiny hairs called cilia lining the respiratory tract help in expelling foreign material. In addition to this, macrophage cells attack and expel the dust particles reaching the lower respiratory passages. ### 2. Skin Absorption Next to inhalation, absorption through the skin forms the main route of entry of chemicals into the body. Absorption through the skin can happen when the chemical handled comes in contact with unprotected body parts. This happens when the person handling the chemicals is not wearing appropriate clothing or personal protective equipment. Cuts and abrasions on the skin can be a source of absorption of the chemical into the blood stream. Chemicals can also be absorbed through the intact skin, for example, phenol splashed on the skin which can be fatal if not promptly flushed off. ### 3. Ingestion This route of entry of chemicals into the body is rare when compared to other means of entry. Ingestion of the chemicals can result from the consumption of contaminated food inside the laboratory, contamination of food stored in refrigerators meant for chemicals, mouth pipetting of chemical solutions, and accidental ingestion of chemicals stored in drinking water bottles and poor personnel hygiene. ### 4. Injection Injection can occur when a sharp object (e.g. needle) punctures the skin and injects a chemical directly into the bloodstream or by a cut from contaminated, broken glassware or sharp knife. ## III. Types of Chemicals Before being started with the types of chemicals there are some terms that explain the health effects of exposure to chemicals. ### 1. Corrosives Examples of corrosives include: - Nitric acid - Sulphuric acid - Calcium hydroxide - Hydrofluoric acid - Sodium hydroxide - Bromine ### 2. Flammables Examples of flammables are: - Acetone - Toluene - Methyl alcohol ### 3. Oxidizers Examples of oxidizers include: - Nitric acid - Perchloric Acid - Permanganates - Nitrates - Perchlorate ### 4. Toxics ### 5. Water Reactive Chemicals Any contact between water or moisture with water reactive chemical materials leads to violent reaction, therefore these water reactive chemicals should be stored far of any source of water and far of wash areas. These water reactive chemicals produce heat or flammable gases if reacted with water, therefore, the dealing with these chemicals must be done in a dry media such as dry bench and dry apparatus. Examples are: - Sodium - Lithium - Potassium ## IV. How chemicals can affect the body According to the structural nature, the chemicals can affect the body in several ways. An examples below illustrates how chemicals can affect the body: **Effects on brain and nervous system** For example: exposure to pesticides, mercury, lead, solvents and carbon monoxide gas. **Eye, nose and throat irritation (dryness, soreness or pain)** For example: exposure to acid mists and vapors, welding fumes or diesel exhaust. **Effects on the lung** - **Lung damage**: For example: asbestos (lung cancer), welding fume (chronic obstructive pulmonary disease). - **Irritant induced asthma**: For example: acids (burn effect on airways). - **Allergic asthma**: For example: flour dust, isocyanate and wood dust. **Liver damage** For example: exposure to vinyl chloride. **Bladder damage** For example: exposure to some azo dyes (bladder cancer).