Lead levels in Maryland construction workers.

A cross-sectional study of unionized construction workers not currently known to be performing lead work was conducted. Participants completed an interviewer-administered questionnaire obtaining information about demographics, work history, other possible sources of lead exposure and health status (including hypertension, noise-induced hearing loss and renal disease). Blood was then obtained via venipuncture for whole blood lead level, hematocrit and free erythrocyte protoporphyrin determination. Two hundred and sixty-four Maryland construction workers had median whole blood lead determinations of 7 micrograms/dl and mean values of 8.0 micrograms/dl, with a skewed distribution ranging from 2 to 30 micrograms/dl. None were currently engaged in known lead work. Blood lead levels were significantly higher for the 124 who had 'ever' worked in demolition (8.8 micrograms/dl vs. 7.2 micrograms/dl, p = .004), and for the 79 who had ever burned paint and metal and welded on outdoor structures compared to the 48 who had done none of these activities (8.6 micrograms/dl vs. 6.8 micrograms/dl, p = .01). The 58 workers who had ever had workplace lead monitoring performed had higher lead levels (9.7 vs. 7.5 micrograms/dl, p = .003). Blood lead levels increased with age, and cigarette smoking. African Americans (N = 68) had higher lead levels (9.1 vs. 7.5 micrograms/dl, p = .01). There were only two women in the study, one with a lead level of 21 micrograms/dl and one, 7 micrograms/dl. Blood lead levels did not predict either systolic or diastolic blood pressure in this population. However, there was a significant interaction between race and lead as predictors of blood pressure, with blacks demonstrating a trend-significant correlation, and whites showing a nonsignificant but negative association. Demolition and hotwork on outdoor structures are known to cause acute episodes of lead poisoning. They also appear to cause slight but persistent increases in blood lead levels. Future workplace regulation should recognize and seek to maintain the low baseline now apparent even in urban, East Coast, construction workers.