Petrochemical plants usually handle invisible gaseous hydrocarbons that could pose safety issues. Leak detection is of vital importance, especially when these gases are toxic, highly flammable, or have a negative impact on the environment. One petrochemical plant, the Borealis high-pressure, low-density polyethylene (LDPE) plant in Stenungsund, Sweden, produces LDPE products for the cable and wire sector, and delivers ethylene, which is converted into polyethylene in a high-pressure polymerization process. This case study tells about how this company uses FLIR optical gas imaging cameras for gas leak detection at a distance and in hard-to-access locations.