The US NRC Radiation Source Regulatory Partnership (RSRP) delivered a virtual training seminar titled, "When to Conduct a Reactive Inspection in Response to a Radioactive Materials Event" to Latin American countries. The seminar was conducted in a two-hour session on November 23, 2021. The seminar provided an overview of the US NRC process to assess and respond to reported events via the discussion of several practical examples. The instructor also discussed the considerations for deciding when to conduct a reactive inspection including the IAEA recommendations for reactive inspections. Attendance of the seminar included twenty-two (22) regulatory staff from Colombia, Dominican Republic, Panama, Peru, and Uruguay.