Germany’s Autobild continues to bang the drum about HFO-1234yf, an air-conditioning coolant sold by US supplier Honeywell as an “environmentally-friendly” alternative to other refrigerants. Problem is, C02 seems to be not only more environmentally safe, but safer for humans (notably rescue workers) as well…
Though the basic problem is that nobody outside of the manufacturer of the substance has much of an idea of what its real risks are, there are a couple of lines of criticism that researchers want to test.
- Flammability. Honeywell knew HFO-1234yf is flammable, and initially marketed it mixed with a fire extinguishing substance. That igniion-retarding iodine compound was later implicated in ozone depletion, and Honeywell now simply downplays concerns about flammability.
- Toxicity: HFO-1234yf breaks down into trifluoroacetic acid, a phytotoxic substance Autobild calls an “insidious poison.” In an experiment undertaken for Autobild, a chemist exposed a pig’s head to ten grams of the substance and “within a half hour, its skin had turned grey and its eyes had become dull and milky.”
- Alternatives: German automakers abandoned HFO-1234yf in 2007 for these very reasons, but went back on their decision in 2009. Industry-watchers blame lobbying and the automakers’ desire to increase the volume of their orders from Honeywell (which also supplies other systems) for the about-face, although the official reason was that the main alternative (C02) was more expensive. Autobild argues that this is a specious argument, as C02 is a far cheaper refrigerant, and that it amortizes its extra up-front cost after “a few refills.”
Rescue workers are now leading the charge to undertake independent testing of the coolant, which was first produced in 1946. Alex Lechleuthner, Head of the Cologne Fire Brigade’s Department of Emergency Medicine says there are “very high operational and personnel expenses” associated with such tests, but that they independent testing is crucial as “previously known information from the manufacturer could be judged very differently depending on the viewing angle.”
And there’s more than just the possible risk of eye-dulling toxicity for rescue workers: according to one EPA document’s abstract:
Automobile air conditioning HFO-1234yf emissions are predicted to produce concentrations of TFA (trifluoroacetic acid) in Eastern U.S. rainfall at least double the values currently observed from all sources, natural and man-made. Our model predicts peak concentrations in rainfall of 1264 ng L(-1), a level that is 80x lower than the lowest level considered safe for the most sensitive aquatic organisms.
But what kind of world would we live in if C02 emissions were less harmful than their alternatives? Especially if one of those alternatives were proprietarily manufactured by a supplier that could charge $150 per kilo for the stuff? Well, when faced with the Autobild attack, that very supplier Honeywell responded [presentation PDF here], arguing that
The new gas has already been approved for use in the US, Japan and Europe and was recently given the all clear by the German firefighter association Deutscher Feuerwehr Verband (DFV) which said it was convinced it had the same safety standards as R134a. The DFV described the toxicity of R1234yf as low and comparable to R134a and was safe for passengers and emergency services.
The chemical manufacturers point out that HFO1234yf has undergone significant testing for safety and efficacy by independent testing groups, including the SAE International Cooperative Research Program, which comprises leading automakers. The SAE testing found HFO1234yf to offer “superior environmental performance” to CO2 while having “the lowest risk for use in mobile air conditioning systems in meeting environmental and consumer needs.”
Separately the EPA reports [PDF] that the SAE test found that
the risk for excessive HF exposure is less than one ten-thousandth the risk of a highway vehicle fire and one fortieth or less of the risk of a fatality from deployment of an airbag during a vehicle… The highest risk identified for HFO-1234yf is potential consumer exposure to HF from decomposition and ignition, which is of the same order of magnitude of risks of HF from the current most common automotive refrigerant, hydrofluorocarbon collision
Dig around long enough and you’ll find a middle ground in HFO-1234yf analysis, like this one from the Auto Parts Accessories Journal, which identifies the long-term risks of TFA buildup and Honeywell/DuPont’s monopoly on supply (and the resulting high price of the substance) as the two major drawbacks of the coolant. That piece concludes
As people who love good engineering, we admit to being just a bit regretful that the CO2 systems were not at least given a chance to prove themselves. It’s difficult to believe that in terms of total environmental impact, from manufacture, distribution, maintenance and actual use, that CO2 would not have a greatly reduced environmental impact over any complex chemical refrigerant. We’ve just emerged from an era where the poor decisions of major automakers have caused their businesses to collapse. Often those decisions were made on the basis of what was most convenient, rather than what mechanics would recognize instantly as good technologies. Let’s be hopeful that HFO-1234yf turns out to be a good technology, and not just a convenient one.
We had better hope that’s the case, as the forthcoming 2013 GM products will be the first in the US market to use HFO-1234yf, starting next year.