HCFC Link To Liver Disease Challenged
LONDON (CNI)--Industry sources have dismissed fears of a health risk from HCFC gases used in air-conditioners, following publication of a new study which finds a link with liver disease.
A study due to be published in Saturday's edition of The Lancet, a UK-based medical journal, found that nine workers in a smelting plant suffered liver disease after they were exposed to HCFC 123 (1,1-dichloro-2,2,2-trifluoroethane) and HCFC 124 (1-chloro-1,2,2,2-tetrafluoroethane) leaking from a faulty air-conditioning system.
The air-conditioning system had originally been filled with CFC 114, but this had been replaced with a mixture of HCFCs 123 and 124 in March 1996. HCFCs are widely used as replacements for ozone-damaging CFCs.
Four months after the refilling, the system was inspected and plastic pipes were discovered to be leaking. The system was then repaired and since then, no new cases of liver disease had been found, the researchers reported.
The scientists concluded: "Repeated exposure of human beings to HCFCs 123 and 124 can result in serious liver injury in a large proportion of the exposed population…In view of the potentially widespread use of these compounds, there is an urgent need to develop safer alternatives."
But industry sources challenged the validity of the study. Jim Wolf, head of government affairs at American Standard Companies, which owns one of the largest US air-conditioning manufacturers, Trane, told CNI: "It makes no sense to link it to 123 and 124 - there has never been any evidence that this relationship exists." There was no information in the study on exposure levels or the length of exposure, he said.
Air-conditioning systems using HCFC 123 - known as centrifugal chillers - kept the gas contained in a closed unit contained in an equipment room, he said. The system cooled water which was circulated through the building and the gas itself would not go beyond the control room unit. Leakage rates would be no more than 0.5%/year, he said.
"No-one in this country would ever put these chemicals in plastic pipes," he said. HCFC 124 was never used in air conditioning, but primarily as a feedstock to make other chemicals.
The American occupational health exposure limit for HCFC 123 had recently been relaxed from 30ppm to 50ppm, Wolf said.
The Lancet study was carried out by a research team headed by Perrine Hoet of the industrial toxicology and occupational medicine unit at the Catholic University of Louvain, Brussels, Belgium.
A study due to be published in Saturday's edition of The Lancet, a UK-based medical journal, found that nine workers in a smelting plant suffered liver disease after they were exposed to HCFC 123 (1,1-dichloro-2,2,2-trifluoroethane) and HCFC 124 (1-chloro-1,2,2,2-tetrafluoroethane) leaking from a faulty air-conditioning system.
The air-conditioning system had originally been filled with CFC 114, but this had been replaced with a mixture of HCFCs 123 and 124 in March 1996. HCFCs are widely used as replacements for ozone-damaging CFCs.
Four months after the refilling, the system was inspected and plastic pipes were discovered to be leaking. The system was then repaired and since then, no new cases of liver disease had been found, the researchers reported.
The scientists concluded: "Repeated exposure of human beings to HCFCs 123 and 124 can result in serious liver injury in a large proportion of the exposed population…In view of the potentially widespread use of these compounds, there is an urgent need to develop safer alternatives."
But industry sources challenged the validity of the study. Jim Wolf, head of government affairs at American Standard Companies, which owns one of the largest US air-conditioning manufacturers, Trane, told CNI: "It makes no sense to link it to 123 and 124 - there has never been any evidence that this relationship exists." There was no information in the study on exposure levels or the length of exposure, he said.
Air-conditioning systems using HCFC 123 - known as centrifugal chillers - kept the gas contained in a closed unit contained in an equipment room, he said. The system cooled water which was circulated through the building and the gas itself would not go beyond the control room unit. Leakage rates would be no more than 0.5%/year, he said.
"No-one in this country would ever put these chemicals in plastic pipes," he said. HCFC 124 was never used in air conditioning, but primarily as a feedstock to make other chemicals.
The American occupational health exposure limit for HCFC 123 had recently been relaxed from 30ppm to 50ppm, Wolf said.
The Lancet study was carried out by a research team headed by Perrine Hoet of the industrial toxicology and occupational medicine unit at the Catholic University of Louvain, Brussels, Belgium.