On any site, the greatest enemy is the unknown. Some of the problems associated with disused underground services are listed below. The following can become an 'environmental issue' and/or health hazard if not approached clinically at the time of discovery. • Awareness of Dangers: being underground, it is often assumed that there isn't a problem. The first and most important factor is to be aware that disused underground services can pose a health hazard! • Location of Disused Services: old services can date back to the late 1800s, with little or no record of their whereabouts. Do not assume that an 'as fitted' drawing shows the precise location of a service. • Live or Capped Services: it is often assumed that a service is no longer energized or under pressure if old drawings either do not show it or it is marked as being 'capped off'. This is a potentially hazardous assumption. • Redevelopment Delays: in areas of redevelopment, disused underground services are at least a nuisance, causing costly delays, and at worst can cause fatalities. • Increased Contractor Costs: gas and electricity engineers called to assess a service, 'dead or alive', may only have current information available. Until the questions of energizing and routing are verified, demolition or construction work is regularly suspended with resultant delays causing oncost nightmares to the contractor. • Levels of Complexity: some site investigations reveal layers of water, gas and electricity services in close and complex proximity to each other. It is imperative to identify and remove unwanted redundant systems prior to the laying of new services. In this way further confusion and health and safety issues are avoided.