Safety with Chemicals

Chemistry is a subject that involves various fascinating materials continuously developed for better living standards.
Many chemicals are utilized across different sectors (industry, medicine, schools, universities, homes) and can pose health risks.
Hazards arise because chemicals may interact with human body parts (internally or externally).
Dangers include not only health risks but also potential interactions with common substances like water and air, which may cause property or environmental damage.
Laws exist at national and state levels aimed at ensuring that individuals working with hazardous chemicals understand safe handling practices.
Harmful chemicals are categorized under dangerous goods or hazardous substances.

Definition: Dangerous goods are chemicals that pose potential dangers to people, property, or the environment.
These goods are classified into nine classes based on the immediate risks they present.
Classifications are often illustrated through GHS (Globally Harmonized System) hazard pictograms.
It is mandatory for dangerous goods to have appropriate signs identified on their labels.

Definition: Hazardous substances are chemicals impacting human health, which can result in immediate effects (poisoning or burns) or long-term effects (liver disease, cancer).
Routes of entry into the body include:
  - Inhalation (breathing in fumes)
  - Absorption through the skin
  - Ingestion (swallowing)
  - Injection
Labels of hazardous substances display a signal word or the word ‘Hazardous’ printed in red.
  - Possible signal words include:
    - Dangerous poison
    - Poison
    - Warning
    - Caution
Labels must also contain information regarding:
  - Risks associated with the substance
  - Directions for use
  - Safety information
  - First aid instructions
  - Emergency procedures
If a hazardous substance is also classified as dangerous goods, the label will include the respective diamond sign identifying its class.

Employers are legally required to ensure that employees are well-informed about chemicals identified as dangerous goods or hazardous substances used in the workplace.
A comprehensive listing of all such chemicals must be maintained alongside each chemical's Safety Data Sheet (SDS).
Chemical suppliers must provide an SDS for every hazardous substance or dangerous good they supply, and employers are responsible for providing access to these sheets for employees.
Typical composition of an SDS spans several A4 pages and may be obtained via the internet or from manufacturers.
Essential information contained within an SDS includes:
  - Ingredients of the product
  - Date of issue (must be no more than five years old)
  - Health hazards and first aid instructions
  - Precautions needed when using the product
  - Information related to safe storage and handling.
Consideration of chemical concentration is crucial. For example, lab experiments often use dilute acids, while concentrated acids are significantly more dangerous, requiring added caution.
- To safely dilute an acid, it is crucial to add acid to water rather than vice versa, as adding water to acid can cause excessive heat generation, leading to burn risks and equipment damage.

A risk assessment identifies potential hazards associated with an experiment, providing protective measures to minimize risks.
Before experimenting with chemicals in school laboratories, a risk assessment must be conducted, which can vary in format but typically includes:
  - Summary of the experiment
  - List of risks and safety precautions for each chemical
  - Classification of chemicals as hazardous or dangerous goods
  - List of protective measures to be taken (e.g., use of fume hoods, safety glasses, gloves, etc.)
  - First aid information.
Most information contained in a risk assessment derives from the SDS of each chemical involved.
The date on the utilized SDS must be noted to ensure the risk assessment is current.
Risk assessment sheets are usually completed and signature by a qualified science teacher or laboratory technician.
Teachers must review the risk assessment sheet before permitting any chemical experimentation to begin.

Key protective measures aimed at minimizing risk include:
  - Wearing safety glasses
  - Using gloves and appropriate protective clothing
  - Performing work in a well-ventilated area
  - Avoiding disposal of dangerous chemicals down the sink.
Corrosive chemicals should be stored in chemical-resistant containers.

Figure 5.5: Depicts the nine GHS pictograms
Figure 5.6: Displays an example of a hazardous substance label
Figure 5.7: Represents a part of a risk assessment sheet for a laboratory investigation.

Section 5.3 concludes with a quick quiz comprising questions to reinforce understanding regarding chemical hazards and safety protocols.