Environmental and safety issues are becoming ever more important in the LNG (liquefied. natural gas) process industry. As plants, pipelines and storage facilities become larger in scale and more complex, maximising safety and minimising risk requires an absolute understanding. It is estimated that more than 400 liquefaction, receiving and storage facilities are either operating, under construction or planned today. This effectively equates to more than 500 storage tanks and well in excess of 1000 km of pipeline that requires monitoring. Modern monitoring technologies such as the nonintrusive fibre optic DTS (distributed temperature sensing) can overcome the limitations of traditional measurement methods and have the capability to instantly pinpoint the precise location of a cool-down or leak event for remedial action. DTS with its intrinsically safe passive sensing cable with a design life of more than 30 years enables the capture of data every metre, and cryogenic leaks can be reported to the ESD (emergency shutdown) system within 15 seconds. No welds are required to the pipe or vessel, and the fibre can be easily strapped to the outside of the pipe with no interruption to the operational process, providing its own communications path without additional tie cables. It can interface with existing SCADA (supervisory control and data acquisition) and ESD or fire and gas control systems using standard protocols. The DTS system can be used in digital leak detection and thermal profiling applications, including LNG, LPG (liquefied petroleum gas), ethylene and CO2 loading and unloading pipelines, storage tanks, spill channels and impounding basins, as well as the cool-down monitoring of pipes and storage tanks. DTS is the only leak detection technique that can monitor an LNG facility in realtime and provide precise temperature and leak information to the nearest metre.