Since pipelines are buried underground, line markers are used to indicate their approximate location along the route. The markers can be found where a pipeline intersects a street, highway or railroad. Markers display the material transported in the line, the name of the pipeline operator, and a telephone number where the operator can be reached in the event of an emergency.
Markers indicate the general location of a pipeline.
They cannot be relied upon to indicate the exact position of the pipeline they mark. Also, the pipeline may not follow a straight course between markers. While markers are helpful in locating pipelines, they are limited in the information they provide. They provide no information, for example, on the depth or number of pipelines in the vicinity. Sight, sound, and smell are helpful in detecting pipeline leaks.