CHE 10 Chapter 1: Chemical Safety

Chemical Safety Overview

• Essential for environments involving chemical use to prevent health issues and environmental damage.
• Chemical safety encompasses the entire lifecycle of chemicals: manufacture, transport, use, and disposal.
• Distinction between hazard (potential to cause harm) and risk (likelihood of harm).

Routes of Entry

• Inhalation: Most common entry; can lead to effects from irritation to severe lung damage.
• Ingestion: Occurs when contaminated food or hands transfer chemicals into the bloodstream, potentially harming organs.
• Absorption: Chemicals can irritate or destroy skin and eyes upon contact.
• Injection: Occurs via sharp objects contaminated with toxic chemicals, leading to potential internal damage.

Acute and Chronic Effects

• Acute Effects: Immediate health impacts from high-level short-term exposure (e.g., chemical burns), often at high concentrations.
• Chronic Effects: Long-term damage from low-level exposure over time (e.g., lung cancer from asbestos); may be irreversible.

Classification of Chemicals

• Hazards are inherent properties of materials; risk is the potential for harm based on exposure.
• Example: Gasoline is hazardous but can be handled safely with proper precautions.
• Fire Triangle: Essential components for fire are heat source, oxygen, and fuel.

Flash Points and Ignition Temperature

• Flash Point: Lowest temperature at which a liquid emits flammable vapor (e.g., Benzene: -11°C, Diethyl ether: -45°C).
• Ignition Temperature: Minimum temperature for self-sustained combustion independent of external heat (e.g., Carbon disulfide: 90°C).

Causes of Ignition

• Spontaneous Combustion: Occurs when a substance reaches ignition temperature without heat application (e.g., oily rags).
• Ignition Sources: Common in laboratories include Bunsen burners and electrical equipment.

Personal Protective Equipment (PPE)

• Mandatory safety gear includes eye protection, gloves, laboratory coats, and closed-toe shoes.
• Ventilation systems, like chemical fume hoods, crucial for reducing exposure to airborne chemicals.

Hazard Control

• Effective management of spills minimizes risks of injury and environmental harm.
• Hierarchy of Control:
  • Eliminate Hazards: Most effective method.
  • Reduce Risk: Through substitution, isolation, or engineering controls.
  • Administrative Controls: Less reliable methods to reduce exposure.
  • PPE: Last line of defense against hazards.

NFPA Hazard Diamond

• System for identifying specific hazards and severity of materials for emergency responses.
• Focuses on health, flammability, instability, and special hazards related to short-term exposure.

Chemical Spill Management

• Immediate removal of contaminated clothing and washing skin with soap and water.
• Specific cleanup methods:
  • Acids: Use calcined absorbents (e.g., Oil-Dri).
  • Mercury: Requires immediate vacuum cleanup to avoid toxic vapor exposure.
  • Alkali Metals: Smother with graphite and handle with care.
  • Phosphorus: Use wet sand or absorbent for safe disposal.

Disposal of Chemicals

• Waste: Unwanted materials that need disposal.
• Hazardous Waste: Materials posing threats to health and environment, often generated in industrial or healthcare settings.
• Types of Hazardous Wastes:
  • Industrial Wastes: From industrial processes.
  • Infectious Wastes: Containing pathogens that could cause disease.

Explore the essential principles of chemical safety from routes of entry to disposal of chemicals. This quiz covers the classification of chemical hazards, safe storage and handling practices, and effective hazard control measures. Prepare yourself to work safely in environments involving chemicals.