A chemical hazard is a (non-biological) substance that has the potential to cause harm to life or health. Chemicals are widely used in the home and in many other places. Exposure to chemicals can cause acute or long-term detrimental health effects. There are many types of hazardous chemicals, including neurotoxins, immune agents, dermatologic agents, carcinogens, reproductive toxins, systemic toxins, asthmagens, pneumoconiotic agents, and sensitizers. In the workplace, exposure to chemical hazards is a type of occupational hazard. The use of protective personal equipment(PPE) may substantially reduce the risk of damage from contact with hazardous materialsLong-term exposure to chemical hazards such as silica dust, engine exhausts, tobacco smoke, and lead (among others) have been shown to increase risk of heart disease, stroke, and high blood pressure.
The decisions you make concerning the use of chemicals in the laboratory should be based on an objective analysis of the hazards, rather than merely the perception of the risks involved. Once this has been accomplished, a reasonable means of controlling the hazards through experimental protocol, work practices, ventilation, use of protective clothing, etc., can be determined.
In order to assess the hazards of a particular chemical, both the physical and health hazards of the chemical must be considered.
Before using any chemical, the safety data sheet (SDS) or other appropriate resource should be reviewed to determine what conditions of use might pose a hazard. Accidents with hazardous chemicals can happen quickly and may be quite severe. The key to prevention of these accidents is awareness. Once the hazards are known, the risk of an accident may be reduced significantly by using safe work practices.
The most common exposure route to chemicals in the work environment is through inhalation. Gas, vapour, mist, dust, fumes, and smoke can all be inhaled. Those with occupations involving physical work may inhale higher levels of chemicals if working in an area with contaminated air. This is because workers who do physical work will exchange over 10,000 litres of air over a 8-hour day, while workers who do not do physical work will exchange only 2,800 litres. If the air is contaminated in the workplace, more air exchange will lead to the inhalation of higher amounts of chemicals.
Chemicals may be ingested when food or drink is contaminated by unwashed hands or from clothing or poor handling practices.
Chemical exposure to the skin is a common workplace injury and may also occur in domestic situations with chemicals such as bleach or drain-cleaners.. The exposure of chemicals to the skin most often results in local irritation to the exposed area. In some exposures, the chemical will be absorbed through the skin and will result in poisoning. The eyes have a strong sensitivity to chemicals, and are consequently an area of high concern for chemical exposure. Chemical exposure to the eyes results in irritation and may result in burns and vision loss.
Injection is an uncommon method of chemical exposure in the workplace. Chemicals can be injected into the skin when a worker is punctured by a sharp object, such as a needle. Chemical exposure through injection may result in the chemical entering directly into the bloodstream.
Types of Health Effects :-
A chronic health effect is an adverse health effect resulting from long-term exposure to a substance. Symptoms do not usually subside when the exposure stops. Examples of chronic health effects include asthma and cancer.
Acute health effects can be observed immediately or soon after an exposure; often a large, brief exposure. Many times the symptoms will subside after the cause is removed, however, depending on the amount/dose, permanent damage or even death can occur from a single exposure. Examples of acute health effects include dizziness, skin irritation, and throat irritation.
Keep in mind that a chemical may cause both acute and chronic effects. Health effects can vary depending on the organ, the dose level, frequency, duration, and route of exposure (inhalation, skin contact, etc.).
Ethanol is an excellent example of a compound that causes varied health effects based on the parameters mentioned above. A small amount of ethanol (from alcoholic beverages) over several hours results in loss of coordination and impaired judgement; large one-time consumption leads to vomiting, unconsciousness, or even death; consumption over several days by a pregnant person can lead to birth defects; and chr:onic consumption over many years can lead to cirrhosis of the liver.
Signs and symptoms of chemical exposure:-
Signs of an exposure are external and can often be seen by you or others in the laboratory. They are objective and can sometimes be measurable. Signs of exposure sometimes include hives, puffiness, sneezing, etc. They are often temporary and can go away when the source of the exposure is removed.
Symptoms are internal and are not visible to the naked eye. They are only felt by the person feeling them and examples include pain, dizziness, numbness, etc.
Sometimes a sign can indicate a symptom. For example vomiting is a sign than indicates someone is feeling nauseated (symptom).
There are different signs/symptoms of exposure to chemicals based on their hazards, reactivity, and the route of exposure. Many of the signs and symptoms of exposure to chemicals are similar, but there are some specific signs which are indicative of particular compounds. For example, osmium tetroxide vapors damage the cornea of the eye, can make your eyes feel gritty, and even turn them black. It is important to know the signs and symptoms of the chemicals with which you work and other chemicals in the laboratory to which you could potentially be exposed.
Symbols of chemical hazards:-
Hazard pictographs are a type of labeling system that alerts people at a glance that there are hazardous chemicals present. The symbols help identify whether the chemicals that are going to be in use may potentially cause physical harm, or harm to the environment. The symbols are distinctive, as they are shaped like diamonds with red borders. These signs can be divided into:
1. Explosive (exploding bomb)
2. Flammable (flame)
3. Oxidizing (flame above a circle)
4. Corrosive (corrosion of table and hand)
5. Acute toxicity (skull and crossbones)
Hazardous to environment (dead tree and fish)
6. Health hazard/hazardous to the ozone layer (exclamation mark)
7. Serious health hazard (cross on a human silhouette)
8. Gas under pressure (gas cylinder)
These pictographs are also subdivided into class and categories for each classification. The assignments for each chemical depends on their type and their severity.
First aid :-
In case of emergency, it is recommended to understand first aid procedures in order to minimize any damage. Different types of chemicals can cause a variety of damage. Most sources agree that it is best to rinse any contacted skin or eye with water immediately. Currently, there is insufficient evidence of how long the rinsing should be done, as the degree of impacts will vary for substances such as corrosive chemicals. However, the recommended flush time is as follows:
1. 5 minutes – non- to mild irritants
2. 15 minutes – moderate to severe irritants and chemicals that cause acute toxicity
3. 30 minutes – most corrosives
4. 60minutes – strong alkalis such as sodium, potassium or calcium hydroxide.
Transporting the affected person to a health care facility may be important, depending on condition. In the case that the victim needs to be transported before the recommended flush time, then flushing should be done during the transportation process. Some chemical manufacturers may state the specific type of cleansing agent that is recommended.
MORE DIFFERENT KIND OF HAZARD :-
1. Anthropogenic hazard – Hazard caused by human action or inaction
2. Biocontainment – Physical containment of pathogenic organisms or agents in microbiology laboratories
3. Biological agent – Pathogen that can be weaponized
4. Biological hazard – Biological material that poses serious risks to the health of living organisms
5. Biosafety level – Level of the biocontainment precautions required to isolate dangerous biological agents
6. Chemical safety – means of ensuring that chemicals are safe
7. Hazard – Substance or situation which has the potential to cause harm to health, life, the environment, property, or any other value
8. Health hazard – Hazards that would affect the health of exposed persons.Hierarchy of hazard controls – System used in industry to eliminate or minimize exposure to hazards
9. Mechanical hazard – Hazard with a mechanical energy source
10. Occupational exposure banding – Process to assign chemicals into categories corresponding to permissible exposure concentrations
11. Occupational hazard – Hazard experienced in the workplace
12. Physical hazard – Hazard due to a physical agent
13.Planetary protection – Guiding principle in the design of an interplanetary mission, aiming to prevent biological contamination of both the target celestial body and the Earth
14. Psychosocial hazard – Occupational hazard to one’s psychological well-being
Public health – Preventing disease, prolonging life and promoting health through organized efforts and informed choices of society and individuals .