Abstract: A fluid injection and monitoring apparatus for the introduction of one or more fluid additives to a gaseous or liquid stream, and for monitoring the stream, such that the additives will be able to be introduced without providing a point of weakness in the pipeline, includes at least two pipe members extending radially into a pipeline, with each of the pipe members having a conduit for flow of a fluid additive material radially inward along the pipe members. A plurality of discharge orifices are provided in each of the pipe members on a downstream side thereof, with the plurality of discharge orifices being arranged in a spaced array along a respective pipe member for discharge of one or more additives downstream into said gaseous or liquid stream.