Daniels, W.J.; Hales, T.; Seligman, P.
An investigation was made at the Louisiana-Pacific Corporation, Olathe, Colorado, of respiratory problems possibly due to exposures at the workplace. The company produced waferboard using a heat- and pressure-cured resin/wax binding material containing 4,4-methylenediphenyl-isocyanate (MDI). Thirteen cases of pulmonary disease (12 cases of asthma and one case of hypersensitivity pneumonitis) were identified by medical testing in three current and 10 former employees. Two of 23 personal air samples contained quantifiable concentrations of MDI, for time-weighted average concentrations of 0.015 and 0.016 mg/cu m, below the NIOSH recommended exposure limit of 0.05 mg/me. The authors conclude that a potential health hazard existed from airborne exposure to diisocyanates. There may be a risk of significant exposure during maintenance activities if proper personal protective equipment is not used. Previously sensitized workers may react at very low concentrations. The authors recommend that engineering controls be maintained at a high level, that good housekeeping practices be adhered to, that a regular program of air monitoring be instituted, that signs warning the danger of exposure to diisocyanate be posted, that employees be instructed in the use of personal protective equipment, and that a program for medical screening be adopted.