The study has two main aims: (1) to analyze and validate the factor structure of the Fear of COVID-19, Workplace health and safety training, and Behavioral Safety Compliance scales (Study 1) in frontline Spanish COVID-19 workers from different sectors (food sector, hospitals, and death care services); and (2) to analyze and validate the factor structure of a reduced version of these scales (Study 2) in Spanish workers in the healthcare sector. Analyses carried out using R 1.4.2. allowed us to validate the factor structure of the scales in the two studies. The sample consisted of 361 participants in study 1; and 708 participants in study 2. The results indicate that the instruments offer adequate evidence of reliability and validity. The questionnaire (especially the short version) can be used by employees who were in frontline of COVID-19 in a reliable and valid way in the post-COVID-19 period, and even to prevent potential similar events that might threaten professionals' physical and mental health in the future.