02/01/1994 - "It was concluded that in the present study, the "no-observed-adverse-effect level" of polymeric MDI was 0.2 mg/m3, and that chronic exposure to polymeric MDI at a level of 6.0 mg/m3 was related to the occurrence of pulmonary tumors. "
02/01/1994 - "It was also concluded that exposure to polymeric MDI at concentrations not leading to recurrent lung tissue damage will not produce pulmonary tumors."
02/01/1994 - "The incidence and distribution of other types of tumors were not influenced by polymeric MDI. "
02/01/1994 - "The time sequence of the spectrum of pulmonary changes indicates that recurrent alveolar wall damage by polymeric MDI and/or polymeric MDI-containing alveolar macrophages leads to alveolar bronchiolization and ultimately to bronchioloalveolar tumors. "
02/01/1994 - "In a second 13-week study with 6-week-old rats, using exposure concentrations of 0, 4.1, 8.4, and 12.3 mg polymeric MDI/m3 (95% < 5 microns) and including a 4-week recovery period, 12.3 mg/m3 induced mortality, growth retardation, severe respiratory distress, increased lung weights, degeneration and hyperplasia of the nasal epithelium, accumulations of macrophages in the lungs and mediastinal lymph nodes, and focal inflammatory changes in the lungs.(ABSTRACT TRUNCATED AT 250 WORDS)"