The invention provides a gas injector (50) for a molten metal vessel, comprising: a gas inlet chamber (51) having an inlet port and at least one outlet port (54), each said outlet port (54) having secured gas-tightly thereto an extruded rod (60) which extends to a gas discharge end (59) of the injector, the extruded rod (60) being formed of a substantially gas-impermeable refractory material and having at least one axially-extending gas passage therealong, the passage communicating with the gas inlet chamber (51), and being of such small dimensions that in use, melt is substantially unable to intrude into the or each passage, the rod and compression gland connector being embedded in a refractory body of the injector save for the discharge end of the rod.