Ten Cases of Acute Lead Intoxication among Bridge Workers in Louisiana

Abstract

We report the cases of ten construction workers who developed acute lead intoxication while repairing a bridge in Louisiana. All but one patient received a five-day course of edetate calcium disodium (calcium EDTA) chelation therapy; one patient received five doses instead of five days of treatment. Calcium EDTA 25 mg/kg q12h was administered for ten consecutive doses by intravenous infusion over two hours. Each dose was diluted in NaCl 0.9% 500 mL. No adverse drug effects were observed during treatment. The posttreatment mean whole blood lead (PbB) concentration was significantly reduced compared with the pretreatment mean PbB (1.48 ± 0.70 vs. 3.8 ± 1.68 μmol/L; p=0.0012, Student's paired t-test). This indicates that the body lead burden of these patients was effectively reduced with calcium EDTA. Eight patients had complaints on admission that were suggestive of lead intoxication. These included malaise, numbness of the extremities, arthralgia, myalgia, abdominal discomfort, sleep disturbance, and lower back pain. Patients had no complaints on discharge. Eight patients had mild anemia that was consistent with acute lead intoxication (mean pretreatment hemoglobin (± SD), 128.6 (± 17.2 g/L), but calcium EDTA therapy did not appear to effect any change in the pretreatment hemoglobin values. The Occupational Safety and Health Administration (OSHA) lead standard requires that manufacturers provide employees at risk for occupational lead exposures with proper respirators and medical surveillance to prevent lead intoxication. The construction industry is exempted from these standards except in Maryland. We believe that amendment of the OSHA lead standards, to provide specific lead regulation of the construction industry, would be helpful in preventing similar cases of occupational lead intoxication.