The aim of the study is to evaluate the effect of the Education Program based on the Mastery Learning Model for Chemical, Biological, Radiological, and Nuclear threats and hazards (MLM-CBRN Education Program) on student nurses' knowledge, attitude, self-efficacy, and skill development in chemical, biological, radiological and nuclear threats and hazards. The complete experimental design type was used in the study.

The aim of the study is to evaluate the effect of the Education Program based on the Mastery Learning Model for Chemical, Biological, Radiological, and Nuclear threats and hazards (MLM-CBRN Education Program) on student nurses' knowledge, attitude, self-efficacy, and skill development in chemical, biological, radiological and nuclear threats and hazards. The complete experimental design type was used in the study. The study sample comprised 104 4th-year nursing students (52 in the experimental group, 52 in the control group). The MLM-CBRN Education Program was carried out with the students in the experimental group face-to-face as theoretical and practical education once a week for four weeks. As a criterion for starting a new unit, 80% of the participants needed to receive minimum 70 points from the unit follow-up tests in line with the "Learning Objective" determined within the scope of the Mastery Learning Model. The data were collected before and right after the intervention and in the 1st and 3rd months after the intervention using the "Personal Information Form," "Nursing Student CBRN Knowledge Test," "Nursing Student CBRN Attitude Scale," and "Nursing Student CBRN Self-Efficacy Scale." Moreover, only the knowledge scores of the students in the experimental group were collected using the unit follow-up tests, which enabled us to check whether the "Learning Objective" related to the unit taught was achieved. During the skill training, the "START Triage and JumpSTART Triage Skill Check List," Gas Mask Wearing-Removing Skill Check List, and Level C Clothes Wearing-Removing Skill Check List were scored for each student in the experimental group after observing the students twice.

Inclusion Criteria:

• Being a senior nursing undergraduate student
• Not having received CBRN training

Exclusion Criteria:

• Be a full-time worker in a healthcare institution
• Having taken courses on disaster and CBRN

if requested; training plan, data collection forms used, presentation content used, checklists used, unit follow-up tests used, and case examples used can be shared.

1-12 months

have ethics committee approval, Researchers who want to do meta-analysis or systematic review