The principal hazard is from striking a buried, live electric cable. With high-voltage cables, this normally results in an explosion and fire causing flash burns to the face, hands and upper body of anyone adjacent to the boring equipment or backhoe. Molten metal from the cable and stones may be ejected at high pressure and speed, causing deep burns that are contaminated with soil and other materials.
Burns are potentially serious and often fatal as they commonly lead to kidney failure in the days following the accident. Electrocution is rarely the cause of death. A cable strike by a backhoe (JCB) may cause the whole machine to be live but is less likely to be fatal provided the operator jumps clear of the live machine.
Burns may also arise from strikes to buried natural gas pipelines (plastic, cast/ductile iron or steel) or liquefied petroleum gas (LPG) pipeline systems. The latter has a greater potential for the spread of un-ignited gas, being heavier than air (unlike methane/natural gas). Both natural gas and LPG have the potential to travel some distance from the point of damage before dispersing or igniting.
While there is a potential to hit pipelines carrying other products, often at high pressure, these tend to be routed through rural rather than urban areas and are less likely to be struck but the effects can still be significant (for pipelines transporting batched products including aviation spirit and gasoline, for example).
Damage to water pipes, telecommunications, fibre optic, television, railway signal and other cables are lower hazards in terms of potential injury staff and subcontractors. Hitting these kinds of services (e.g. fibre optic cables) tend to have significant cost and operational impacts (e.g. for railways) rather than safety implications.