What Happened?

A laboratory technician punctured their left thumb on a glass coverslip fragment left in a "dirty sink" while cleaning a container contaminated with human fecal matter. The fragment was not visible, and coverslips are normally handled in a different area of the lab. The technician had no reason to anticipate broken glass in the sink. The technician was wearing appropriate PPE, including gloves. They expressed the wound under running water for 15 minutes, reported the incident to their supervisor, and went to the Occupational Health and Safety Facility. Blood samples were drawn as a precaution, and an Infectious Disease physician was consulted, who recommended a follow-up examination.

What Was The Cause?

• Immediate cause: The technician's thumb contacted a glass coverslip fragment concealed in the sink.
• Underlying causes:
  • A broken coverslip was disposed of in the sink rather than a designated broken-glass container.
  • Inadequate routine cleaning allowed debris to accumulate in the sink.
• Root cause: Gap in the lab's waste segregation practice and shared-equipment hygiene — specifically, failure to enforce separation of glass/sharps waste from sink drains, and failure to keep sinks clean. This incident represents a latent-failure hazard: someone else's earlier error (improper disposal) created a dormant hazard that caught a downstream user. In human factors terms, this is a classic latent condition in the sense of James Reason's Swiss cheese model. While proper PPE was worn, it was insufficient to protect the technician. 

How Can Incidents Like This Be Prevented?

• Be diligent with housekeeping, and do not place your co-workers at risk
• Keep track of broken glass and dispose in sharps container
• Minimize contact with potential infectious material by soaking containers that contained feces from infected humans in 10% bleach for 20 min; then wash the container in the sink

Resources

• Risk Group Classification for Infectious Agents
• Pathogen Safety Data Sheets