Abstract

The treatment of wood with sulphite and sulphate derivatives to produce wood pulp releases a variety of pulmonary toxins. The objectives of this project were the identification and quantification of these substances, both at their source and in the workplace air, and the development of corrective measures. The major contaminants associated with the sulphate process are dimethyl sulphide, methyl mercaptan and hydrogen sulphide; sulphur dioxide is the only sulphur-based contaminant emitted during the sulphite process. The location of the emission sources depends on the process cycle (continuous or cyclical), the amount of maintenance the equipment receives (e.g. valve and pipe leaks) and the specific task the operator is called upon to perform (e.g. opening the reaction vessels).

The researchers emphasize the need for the following corrective measures: periodic maintenance and verification of all systems, installation of local exhaust ventilation, sealing off of sewers, installation at key locations of hydrogen sulphide or sulphur dioxide detectors equipped with visual and auditory alarms, and adequate protective equipment. Worker training and information sessions are essential elements of a such a corrective program.