Hepatotoxicity Associated with Overexposure to 1,1-Dichloro-2,2,2-Trifluoroethane (HCFC-123)

Abstract

1,1-Dichloro-2,2,2-trifluoroethane (HCFC-123) was evaluated as a substitute for trichlorofluoromethane (CFC-11), and it appeared that a permissible exposure limit of 50 ppm was justified. When HCFC-123 was introduced as a precision cleaning agent in a controlled operation, marked elevations in serum alanine transaminase and serum aspartase transaminase were noted in exposed workers. Sampling taken during start-up documented personal samples from 24-480 ppm (375 and 21 min, respectively) and area samples of 18-180 ppm (375 and 21 min, respectively). Personal and area samples collected after the liver abnormalities were identified ranged from 5-12 ppm. Exposure data were not available for the period when the abnormalities are suspected to have developed. Two models were developed to estimate exposure during the unmonitored period: (1) the entire plant as a homogenous box and (2) evaporation into smaller work zones. Modeling using the entire building estimated 8-hour time-weighted average (TWA) exposures of 10-35 ppm. Modeled estimates of work area and air exchange rates indicated that degreaser exposed workers could have experienced peak levels of 280-2,100 ppm (8-hour TWAs 252-1,630 ppm). Modeling of the work environment, estimated to be one-third of the volume of the entire open building, indicated peak exposures of 28-210 ppm (8-hour TWAs 25-163 ppm). These ranges estimate the minimum and maximum exposure levels. The best estimates, using 12 air changes per day, suggest peak levels around the degreaser of 635-2,100 ppm (8-hour TWA 499-1,630 ppm) and 63-207 ppm (8-hour TWAs 50-163 ppm) in the work area. These are the first estimates of exposure level associated with these hepatotoxic effects; all are significantly higher than personal and area samples collected for HCFC-123 after the liver abnormalities were identified.

Evaluating Indoor Exposure Modeling Alternatives for LCA: A Case Study in the Vehicle Repair Industry

“…Despite this rich data set, we demonstrate that the uncertainty of the models evaluated here can be quite large as previously seen [10,35]. In the eddy-diffusion model, values for D must be fitted to the actual exposure data or obtained from the small number of empirical studies that have been published [12, 14-16, 36, 37].…”

HCFC-123-induced toxic hepatitis and death at a Korean fire extinguisher manufacturing facility: a case series

“…As this is a five-fold difference, it appears likely that the background of setting these limits differs greatly. In a 1997 case of HCFC-123-induced hepatotoxicity in the US, the estimated building-wide 8-h TWA exposure was 10–35 ppm [ 10 ]. According to best estimates, the 8-h TWA in the work area was 50–163 ppm.…”

“…Two patients showed maximum AST and ALT levels of 1370 mu/mL and 2675 mu/mL, respectively, or 956 mu/mL and 3001 mu/mL, respectively. All patients eventually recovered [ 10 ]. In Korea, a worker was exposed to refrigerant gas while exchanging refrigerant fluids due to a leakage during refrigerator maintenance.…”

An outbreak of refrigerant-induced acute hepatitis in Hong Kong

“…Moreover, the degree and prevalence of liver dysfunction were higher in the high-exposure group. 7 Urinary concentration of trifluoroacetic acid (TFA), which is a major metabolite of HCFC-123, can be used to determine the degree of HCFC exposure in air. However, in our case, urinary concentration of HCFC metabolite was negative.…”