Near misses, defined by harm averted due to chance or intervention, are low-cost learning opportunities in radiation oncology. We examine effects of near miss type and learning environment characteristics, such as psychological safety (PS) and time for reflection (TF), on incident reporting and recognition as success versus failure. We posit that perceiving the incident as success is correlated with perceptions of departmental willingness to report (WTR), and that these ratings would differ by near miss type. We also assess the relationship of psychological safety (PS) and time for reflection (TR) with departmental WTR. We administered a survey to members of a radiation oncology department with an incident learning system (ILS). The survey presented six incidents (4 near misses, 1 control, 1 hit) for a patient receiving intravenous contrast: process-based catch with harm averted by systematic creatinine check; good catch with harm averted by staff incidentally checking creatinine; could-have happened harm averted by chance normal creatinine; almost-happened harm with patient’s creatinine elevated and no sequelae; hit event with kidney injury; and control event with normal, checked creatinine and no sequelae. Subjects rated each event for success and departmental WTR on a 1-7 Likert scale, and answered validated PS and TF instruments. ANOVA and ordered logistic regression were used to assess WTR and success rating differences among near miss types, correlations with PS and TR, and real incidents coded as near miss in the department’s ILS database between 2014-2018. The survey yielded 97 of 127 responses (76.4%). Within each near miss type, success rating and WTR were negatively correlated (p<0.0001). There was no difference in WTR nor success ratings among near miss types (p=0.87). Male subjects exhibited a greater trend towards WTR hit events compared to female subjects (p=0.058). TR showed a positive trend with almost-happened events (p=0.085) and was significantly correlated with departmental WTR hits (p=0.007). However, TR showed a negative trend in real ILS reporting of near miss incidents (p=0.077). PS for attending physicians was significantly greater than that for therapists (5.68 vs. 3.56, p = 0.001). TF for therapists (4.31, p=0.034), physicists/dosimetrists (4.18, p=0.007), and nurses/medical assistants (4.33, p=0.048) were significantly less compared to that of physicians (5.81). In free text responses, subjects described the ILS as a platform to report “problems.” Near misses perceived as failures (vs. successes) are more likely to be reported, which corroborates the perception of the ILS as a platform to share problems. Greater time for reflection is correlated with the perception of others’ willingness to report harmful events, though less reflection time may be associated with personal ILS submissions, perhaps due to hierarchical role differences.