All volunteers must undergo a three-part background screening (criminal background check, references, and an interview) to ensure there is no history of activity that would pose a danger to children or others.
All volunteers must undergo training concerning child protection.
In any activity involving children, the two-person rule should be followed to avoid any situations in which a single individual (other than a parent of his/her own child) is alone with children.
Specific resources and guidance for churches and volunteer trip team leaders is available here: https://www.imb.org/for-churches/mission-trip-prep/.