What Happened?

An animal technician sustained a needlestick injury to their right index finger while cleaning a push cart used to transport mouse cages and water bottles. An unsheathed needle had been left behind on the cart, obscured from view by the cages and bottles. The technician was pricked by the needle while sanitizing the cart.

The incident is of particular concern because the needle may have been used previously to inject mice with a biohazardous material, creating a potential for biohazard exposure. The technician was wearing full PPE, including double gloves, at the time of injury. They immediately notified his supervisor, who directed him to the Occupational Health Facility for medical evaluation.

What Was The Cause?

• Immediate cause: The technician's finger was pricked by an uncapped needle attached to a syringe that had been forgotten on a cart and was obscured by objects on the cart. The injury occurred during a routine cart sanitization task.
• Underlying causes:
  • Improper sharps disposal: The needle was abandoned on the cart instead of being immediately disposed of in a sharps container after use, a direct violation of standard sharps safety practices.
  • Obstructed line of sight: The cage and bottle arrangement on the top shelf blocked visual inspection before the technician reached onto the shelf, creating a blind-reach hazard
  • PPE limitations: Double gloves, while appropriate for biological contamination protection, do not prevent needlestick penetration — the needle bypassed this control entirely
  • No pre-task hazard check: The technician reached onto the cart shelf without first visually or mechanically clearing the surface of potential hazards
• Root cause:
  • No enforced sharps disposal policy for animal procedure areas: The person who used the needle did not dispose of it immediately and faced no systemic barriers or reminders to do so at the point of use.
  • Lack of a cart clearance SOP: No written procedure required animal care or research staff to clear and visually inspect push carts before handing them off for sanitization or use by others.
  • Accountability gap: The needle was left by an unknown individual, indicating that no tracking or accountability mechanism exists for sharps used during animal procedures on shared equipment
  • Training gaps: Staff conducting animal procedures on shared carts may not have been adequately trained in immediate sharps disposal requirements or in the downstream risks posed to animal care technicians.
  • Shared equipment hazard not addressed in Exposure Control Plan: Push carts used across both research and animal care functions represent a shared exposure pathway that may not have been identified or controlled in the lab's or facility's Exposure Control Plan.

How Can Incidents Like This Be Prevented?

Animal technicians are at the mercy of the research community. The best way to prevent incidents like this:

• Mount a sharps container directly on every push cart used in animal procedure areas, so immediate point-of-use disposal is always available without walking away from the work area.
• Use safety-engineered needles with retractable or auto-sheathing mechanisms so that any needle inadvertently left behind is in a protected state.
• Dispose of sharps immediately at the point of use — never set a needle down on any surface, including a cart shelf, between steps.
• Implement a pre-sanitization cart inspection protocol: animal care staff should visually sweep all cart surfaces, including shelves obscured by cages or bottles, before reaching in.
• Use a long-handled brush or sponge tool rather than bare hands when cleaning cart surfaces, keeping hands away from potential hidden sharps.
• Establish a cart handoff checklist that requires research staff to confirm all sharps have been disposed of before releasing the cart for sanitization by animal care staff.
• Enforce a strict "no sharps left on shared equipment" policy with clear accountability for all staff using push carts during animal procedures.
• Update the Exposure Control Plan to explicitly identify shared mobile equipment (push carts, racks) as a potential biohazard exposure pathway.
• Include cart safety in BBP and sharps training for both research staff (who use the needles) and animal care technicians (who clean the equipment) — both groups need to understand the shared risk

Resources

• Risk Group Classification for Infectious Agents