CITB SSSTS course - Accredited Site Supervisors Safety Training Scheme for the Site Supervisor aka SSSTS training courses The Supervisors Safety Training Scheme is now a requirement set out by The Major Contractors Group for all supervisors who will be working on their sites. Construction skills and health and safety need to go hand in hand and made a priority to encourage improved work skills and reduced accidents and injuries. Not only is the SSSTS course a must put in place by the MCG, it is also ideal for anyone looking to take on a supervisory role within the construction industry.