Serious swimming pool incidents are thankfully rare but they can almost be totally avoided if supervision is backed up by appropriate, practical, technology.  Each year in the developed world several hundred people drown in municipal, hotel, school, and sports club pools.  An even greater number survive ‘near drowning’ ….. A proportion of these with varying degrees of brain damage.  This is the result of being revived late in the course of an incident and is caused by oxygen starvation. Human supervision is by far the ‘best’ at identifying those at risk.  However humans can be less consistent over extended periods of time than would be ideal, incredibly capable but subject to fatigue, distraction, boredom and impaired visibility.  We are clearly at our best when responding to ‘events’ – either directly recognised or when we are alerted to them by others or by appropriate technology.  SenTAG is designed to provide supervisors with an early qualified ‘alert’ so that they can do what they are best at – checking out the well being of bathers and dealing with any real incident early and efficiently.  SenTAG was developed because as humans we are fallible – and because today we really can do something about it. Swimming in operator managed pools is relatively safe...and is widely described as such. However each hour of swimming carries a very similar level of risk to those associated with car use. To put this in context pool swimming is therefore considerably more hazardous per hour than many other forms of transport and other sports. Risk is a relative issue, the number of road deaths seems high to us relative to pool swimming - however that is mostly because we all spend so much time in and around cars and are therefore exposed to the risk for much longer periods of time. Groups such as the young and elderly also use pools to a much greater extent than the 'average person'. The risk of pool swimming can be perceived as being low because the average person does not swim for more than a few hours each year in operator managed pools. In the same way fireworks could be considered 'safe' because our time exposure to them is very limited each year - but most of us still, quite rightly, treat them with a respect that is well deserved. SenTAG do not suggest that swimming in operator managed pools is highly dangerous - but we do not believe the risks involved can be casually discounted. Risk needs to be fully understood and managed. Our view is also that most serious pool incidents can be totally avoided, simply, cost-effectively and without fuss. In the last decade something like 150 people have drowned in UK managed pools and up to 1000 are estimated to have survived serious 'near drowning' incidents - a proportion with permanent brain impairment, the result of being detected and revived late. In the US alone it is estimated that 400-500 people are drowned anually in supervised pools and a considerably higher number are presumed to survive 'near drowning'. The vast majority of these incidents are totally avoidable. Nearly all of these 'accidents' could have been prevented.