A method and apparatus for collecting waste liquid at a wellhead from an above ground source conduit when wireline apparatus and/or associated tools are withdrawn from a well includes providing a manually portable waste liquid containment assembly having a valved conduit subassembly that is connected in fluid-tight relation to the source conduit, and admitting waste liquid into the containment assembly at the drilling site. The waste liquid containment assembly includes a water and flame resistant cellulosic container fitted with a plurality of flexible oil and water impermeable polymer bags nested one inside of the other, the innermost polymer bag containing an oil-absorbent natural product. The valved conduit subassembly has components to safely control the waste liquid during the filling of the polymer bags, including a control valve, a check valve and a pressure relief valve. Conduit couplings join the conduits, which can include flexible sections, in fluid-tight mating relation.