Understanding Laboratory Hazards | Safety Measures for a Secure Work Environment | Ep 7

This podcast summarizes crucial information regarding laboratory hazards, encompassing chemical, fire, radiation and general safety protocols.

The provided sources highlight the importance of proper classification, labeling, handling, and storage of hazardous materials to ensure a safe laboratory environment. The materials are practically identical so there is no conflict or difference in the information being provided.

Key Themes and Ideas:

Hazard Classification:
The United Nations (UN) establishes a foundational system for classifying hazardous materials into nine distinct classes.
These include:
Class 1: Explosives
Class 2: Compressed Gases
Class 3: Flammable Liquids
Class 4: Flammable Solids
Class 5: Oxidizer Materials
Class 6: Toxic Materials
Class 7: Radioactive Materials
Class 8: Corrosive Materials
Class 9: Miscellaneous Materials
This classification system is crucial for recognizing and responding to potential hazards.

Warning Labels:

DOT (Department of Transportation) Labels: The DOT mandates that chemicals shipped in the U.S. have labels that correspond to the UN's hazardous material classification. These labels are diamond-shaped with the classification number at the bottom and the hazard type along the horizontal axis.

Crucially, the DOT labels are only on shipping containers. Laboratories are responsible for labeling each individual container within the lab. This ensures safety after the product has been received and stored.

OSHA Mandates: OSHA requires the use of labels or appropriate warnings but doesn't prescribe a single, standardized labeling system.

NFPA (National Fire Protection Association) 704-M System: This system is widely used in labs. It uses a diamond-shaped label with four color-coded quadrants:

Blue: Health hazard
Red: Flammability hazard
Yellow: Reactivity hazard
White: Special hazard information (e.g., poison, water reactivity).
Each quadrant is rated from 0 (least hazardous) to 4 (most hazardous).

Chemical Hazards and Handling:

Spill Kits: Approved spill kits must be readily available in the lab.

Acid Dilution: Concentrated acids should always be diluted by adding the acid to the water, never the other way around, to avoid dangerous reactions.

Container Labeling: All containers must be labeled before chemicals are added.

Chemical Instability: Some chemicals become more dangerous over time. For example, "picric acid [can form] shock-sensitive peroxides".

Specific Hazards: "Sodium azide, a carcinogen, can create explosive metallic salts when disposed of in the sewer," highlighting the importance of appropriate disposal.

Carcinogen Handling: Working with carcinogens requires special precautions like the use of a fume hood and personal protective equipment (PPE).

Glass Transport: Glass chemical containers should be transported in rubber or plastic holders to prevent breakage.

Fire Hazards and Management:
Flammability: Flammability is defined by how easily a substance ignites and spreads flames.
Key Properties: Flash point (the temperature at which vapours form an ignitable mixture with air) and volatility (the ease with which a liquid or solid passes into vapor measured by the boiling point).

Flammable Storage: Common flammable liquids like xylene, ethanol, methanol, and acetone must be stored in a flammable liquid safety cabinet.

Pyrophoric Materials: Pyrophoric materials such as potassium metal can spontaneously ignite.

Flammable Storage Guidelines: Flammable materials should be kept away from acids, stored in cool and well-ventilated areas, never in standard refrigerators, and away from potential ignition sources.

Flammable Handling Guidelines: When handling flammables, gloves and safety goggles are required and flammable liquids should be dispensed in a fume hood or approved storage area. Water should never be used to clean up a flammable liquid spill.

Fire Extinguisher Classification:
Extinguishers are classified based on the type of fire they are meant to extinguish:
Type A: Combustibles (wood, cloth, paper, rubber, plastics)
Type B: Flammable liquids (oil, grease, paint thinners)
Type C: Energized electrical equipment
Type D: Combustible metals (magnesium, titanium, sodium, lithium, potassium)

General radiation safety involves minimizing exposure to harmful radiation to protect health and safety. The guiding principle is ALARA (As Low As Reasonably Achievable).

Here are some key strategies:

Time: Reduce the amount of time spent near radiation sources.
Distance: Increase your distance from the radiation source to lower exposure.
Shielding: Use barriers (like lead or concrete) to block or reduce radiation exposure. These measures help ensure safety in environments where radiation is present.