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In a field study and a subsequently performed cross-sectional study with serial examinations in workers at the same factory, impaired respiration as a result of occupational exposure to DMAPA was noted. Assemblers, a group with the greatest exposure to the epoxy resin system, reported acute symptoms on exposure and showed statistically significant pulmonary function loss. Other groups with less exposure showed changes intermediate between the assemblers and an unexposed control group. Lung function of all individual assemblers decreased over Monday and over the week, suggesting that the airway response was due to an irritant effect rather than hypersensitivity, since in the latter case a large variation of individual responses might be expected. The impaired respiration observed after DMAPA exposure was considered to be attributed to respiratory irritation by DMAPA, already after a single exposure (Brubaker et al., 1979, reliability score: 2, details see 7.10.5).

Additional information

In a field study of 1974, workers showed impaired respiration (wheezy breath, constricted chest, irritation of mucosa of the eyes, nose and pharynx) as a result of occupational exposure to DMAPA (2.34 - 5.87 mg/m³ = 0.55 -1.38 ppm).

In a subsequently performed study in 1977, cross-sectional, serial examination was conducted at the same factory with 34 workers. An average DMAPA concentration of 0.55 mg/m³ (0.13 ppm) was measured in the respiratory zone of the assemblers. Of the 28 persons exposed to DMAPA, 5 complained of irritation of the nasal mucosa and 2 of increased mucous formation in the respiratory tract. Only among the 6 workers with non-specified tasks was a significant reduction (3.9%) in vital capacity found at the end of the first working day of the week compared with results obtained prior to starting work. Neither among the assemblers nor among the pressmen was any impairment of respiration during the course of the working day observed. Comparison of the data of pulmonary function in the different subgroups showed significant differences between the groups. A LOEL (Lowest-Observed-Effect-Level) would thus be in the range of 0.425 - 0.85 mg/m³ (0.1 - 0.2 ppm).

The impaired respiration observed after DMAPA exposure was considered to be attributed to respiratory irritation by DMAPA. Measurements of lung function showed that no provocation or challenge experiments were necessary to observe lung/respiratory effects after DMAPA exposure, which was evident already after a single exposure due to the corrosive properties of the substance (Brubaker et al., 1979)

The lack of an alert for respiratory sensitization was also confirmed by OECD QSAr toolbox (see Read-Across Justification in section 13).