Chemical Hazard Plans

While biological hazards are the primary concern in the initial stages of culture, the harvest and staining phases of Cytogenetics involve aggressive chemicals. The OSHA Hazard Communication Standard (HCS) - also known as the “Right to Understand” law - and the Laboratory Standard (29 CFR 1910.1450) mandate that every laboratory possess a written Chemical Hygiene Plan (CHP). This plan outlines procedures, equipment, PPE, and work practices capable of protecting employees from the health hazards presented by hazardous chemicals

The Chemical Hygiene Plan (CHP)

The CHP is the central operational document for chemical safety. It must be accessible to all employees and reviewed annually. A designated Chemical Hygiene Officer (CHO) is responsible for its implementation

• Standard Operating Procedures (SOPs): The CHP must contain specific protocols for handling high-risk chemicals (e.g., “SOP for mixing Methanol/Acetic Acid Fixative”)
• Designated Areas: The plan must identify specific areas (e.g., a specific fume hood) authorized for the use of “Particularly Hazardous Substances” like carcinogens, reproductive toxins, or acute toxins
• Training: New employees must be trained on the CHP before starting work, and all employees must receive annual retraining

Safety Data Sheets (SDS)

Formerly known as Material Safety Data Sheets (MSDS), these documents are the primary source of safety information. Under the Globally Harmonized System (GHS), SDSs follow a standardized 16-section format

• Accessibility: SDSs must be readily available to staff 24/7. They can be physical binders or digital databases, provided there is a backup method (e.g., a thumb drive or phone number) in case of power/internet failure
• Critical Sections for Laboratory scientist s
  • Section 2 (Hazard Identification): Lists GHS pictograms (e.g., Skull and Crossbones, Flame) and signal words (“Danger” vs. “Warning”)
  • Section 4 (First Aid): Immediate actions to take upon exposure
  • Section 6 (Accidental Release Measures): How to clean up a spill
  • Section 8 (Exposure Controls/PPE): Required gloves, respiratory protection, and ventilation

Specific Chemical Hazards in Cytogenetics

Cytogenetics laboratories utilize a specific set of chemicals that pose unique risks, particularly regarding reproductive health and flammability

• Carnoy’s Fixative (Methanol + Glacial Acetic Acid)
  • Hazards: Methanol is toxic (blindness/death if ingested, absorbed through skin) and highly flammable. Glacial Acetic Acid is corrosive and causes severe burns
  • Handling: Must be mixed and used inside a Chemical Fume Hood, not a Biological Safety Cabinet (BSCs recirculate air; Fume Hoods exhaust chemical vapors out of the building)
• Formamide
  • Use: Used in Fluorescence In Situ Hybridization (FISH) buffers to denature DNA
  • Hazard: A potent teratogen (reproductive toxin). Pregnant laboratory scientist s must be particularly cautious or excused from handling raw formamide depending on lab policy
• Stains (Giemsa/Wright/Leishman)
  • Often methanol-based, posing flammability and toxicity risks
• Xylene
  • Use: Slide cleaning or mounting
  • Hazard: Neurotoxin (dizziness, headache) and flammable. Waste cannot go down the drain

Emergency Procedures: Exposure & Spills

The CHP dictates the immediate response to chemical accidents. The general rule is “Safety of People > Safety of Property.”

• Chemical Spills
  • Minor Spill: If the spill is small, the chemical is known, and the laboratory scientist has the training/supplies, they may clean it up
    • Action: Use the specific Spill Kit
    • Acid Spill: Use a neutralizer (usually bicarbonate-based) until fizzing stops, then absorb
    • Solvent Spill (Methanol): Use activated charcoal or specific absorbent pads to suppress vapors
  • Major Spill: If the spill is large, highly toxic, or in a confined space
    • Action: Evacuate the area, close doors, alert the CHO/Security, and call Hazmat
• Chemical Exposure (First Aid)
  • Eye Contact: Immediately flush eyes at an Eyewash Station
    • Duration: Hold eyelids open and flush for a minimum of 15 minutes
  • Skin Contact: Move to the Safety Shower
    • Action: Remove contaminated clothing (including shoes/lab coat) while under the water. Rinse for 15 minutes
  • Inhalation: Move the victim to fresh air immediately

Labeling & GHS Compliance

All chemical containers must be labeled. This includes the original manufacturer’s bottle and any “secondary containers” (e.g., a Coplin jar used for staining)

• GHS Label Elements
  • Product Identifier: Name of the chemical
  • Signal Word: “Danger” (severe hazard) or “Warning” (less severe)
  • Hazard Statements: Describes the nature of the hazard (e.g., “Causes severe skin burns”)
  • Pictograms: Diamond-shaped symbols with red borders
    • Flame: Flammables (Methanol)
    • Corrosion: Corrosives (Acetic Acid)
    • Health Hazard (Star on chest): Carcinogens/Teratogens (Formamide)
    • Exclamation Mark: Irritant/Acute Toxicity

Storage Rules

Incompatible chemicals must be segregated to prevent dangerous reactions (e.g., fire or toxic gas generation)

• Flammables: Stored in a dedicated, vented yellow safety cabinet
• Corrosives: Acids and Bases must be separated (e.g., separate shelves or tubs)
• Oxidizers: Must be kept away from flammables
• Height: Large bottles of heavy chemicals (acids) should be stored on lower shelves (below eye level) to prevent breakage and injury during retrieval