Blessed by the Potato

I don’t really get it — there is a lot of fear and doubt out there about hybrid cars, a lot of people saying things to detract from the new technology. Some of it is pure bullshit, like the CNW study or the crap about the Sudbury moonscape. Some of it is selective accounting looking at the purely financial side of things, such as comparing a nicely equipped mid-sized car like a Prius to a bare-bones compact, or assuming that the price of gas won’t go up over the next 15 years, or that you’ll only own your car for 7 years at which point it will be worthless.

I can understand why some companies (cough, GM, cough) who are losing out on sales to hybrids might have an interest in sowing FUD, but I’m surprised that so many people out there seem to take it up without a second thought (how many times have I heard “oh, but the batteries will have to be replaced every 5 years”?!). Hybrids are a very promising technology and a vital step on our path to electric cars, and while rare until very recently on the ordinary streets of Canada, aren’t really all that new.

One of the latest rounds of fear-mongering focuses on the electromagnetic fields (EMFs) produced by hybrid cars, getting international attention in a recent New York Times article “Fear but few Facts on Hybrid Risk” which was linked to by the Consumerist. To quote from the article:

Kent Shadwick, controller of purchasing services for the York Catholic District School Board in York, Ontario, evaluated the Toyota Prius for fleet use. Mr. Shadwick said it was tested at various speeds, and under hard braking and rapid acceleration, using a professional-quality gauss meter.

“The results that we saw were quite concerning,” he said. “We saw high levels in the vehicle for both the driver and left rear passenger, which has prompted us to explore shielding options and to consider advocating testing of different makes and models of hybrid vehicles.”

I sent a message to Kent Shadwick, asking if he’d share his data so I could see what he considered “high” and whether that was a static (DC) field or a time-varying field measured. He did respond, and promptly, but only to say that he hasn’t shared the results anywhere, and that they hired an outside company to take the measurements using a rigourous procedure. He also said that he was looking into shielding solutions.

I have to say that this is really disappointing, and I think it shows the real lack of a decent science education in the general public that the New York Times ran this piece without even being able to say what the fields are or how that compares to the geomagnetic field, let alone whether there’s any risk from that. The field, if you will forgive the pun, of bioelectromagnetics is so controversial and so lacking in standards that it means virtually nothing to have one person say that something is “concerning” without knowing what their threshold for concern is. Some people are concerned by static fields that are weaker than the Earth’s magnetic field; some aren’t concerned about static fields at all until we get beyond the MRI level. Likewise with time varying fields: some people think that virtually any exposure should be eliminated, others think nothing of using microwaves up to the point where they cause protein denaturation or other fields up to the point where they start to heat the tissue. I have no idea what Kent Shadwick might find concerning, so even if he does have a respectable position with the school board (not some random nut falling asleep at the wheel) and even if he did hire qualified people to take good measurements with the proper equipment… his “concern” is not really newsworthy to me unless I know how his threshold of concern compares to mine.

Plus all this concern about magnetic fields in hybrids is really only part of the issue.

The question asked is always about the risks — we know, for instance, that ionizing radiation is something that can cause cancer and other health issues. However, if you have a broken arm or get a nasty bump on the head, you can be sure you’re popping in for an x-ray/CT no questions asked because there is a big benefit to those diagnostic tests that far outweighs the small inherent exposure. It’s really all about risk-benefit ratios.

So for the hybrid car issue, we have the question “what are the fields?” and we don’t even have a good answer to that, from which point some people fall into hysterics (up to selling their car). The real issue is then several steps removed: the Prius may have higher magnetic field exposures than other cars, and those fields have an unknown but probably small effect on human health, and that might outweigh the positive aspects of the technology.

One example used to show that pulsed magnetic fields can effect biology is the FDA-approved bone growth stimulator. I had the pleasure last week of listening to Arthur Pilla’s (one of the inventors of the electromagnetic bone stimulator) plenary talk in San Diego. He talked about the first use of the bone stimulator on a woman who had a fractured tibia just below the knee that hadn’t healed for 9 years, despite multiple bone grafts, etc. They had this theory that an electromagnetic stimulator might be able to stimulate bone growth, but they also knew that the fields would not be restricted to just the break, and that the knee itself would also be exposed. There was a real concern that the bone might grow wildly out of control and completely fuse the knee, but since this woman’s only other option was amputation, they gave it a try. The stimulator only caused bone growth where there was a break. My point is that it’s not quite so simple to say that induced currents will have an effect on tissue; they may have an effect on some tissue some of the time.

So ok, there might be some small risk with hybrids (though probably not). On top of that the benefits have to considered (fuel efficiency, emissions, safety…) One colleague off-handedly said that even if magnetic fields cause cancer, you’d probably be better off with a Prius because you’d be exposed to less gasoline from the gas stations and escaped vapours in your garage… another possible carcinogen. To save less fuel than switching to a hybrid would net, some people will tailgate (draft) semi trucks in their blind spot. That’s a behaviour with a definite and immediate risk — not of possibly getting cancer 20 years down the road, but of getting instantly killed by a tire blowout or sudden stop with zero space for reaction time. Of course, the risk of being turned into a red smear on the pavement is not a new type of risk to drivers.

The benefits of a Prius vs. a comparable conventional car are real and material. The risks are unknown, but probably negligible. Unfortunately people have such a fear of the unknown that they can blow it out of proportion in their decision making, and focus on their fears rather than the overall picture. Back to the York Catholic District School Board: as a scientist, I was a little disappointed that he wouldn’t share his results so that I could come to my own conclusions; however, I understand why he went to the effort of measuring the fields and looking into solutions — for an individual driver, the risk-benefit ratio is pretty clear: just buy the hybrid. For a school board fleet however, there are unions to consider, and a union will fuck up a school board over a perceived threat to its drivers, whether or not that’s a real concern or a valid trade-off (after all, it’s not the union members who are saving on gas in a fleet purchase situation, so in their minds the risk-benefit works a little differently).

The title of the article was spot-on: Fear, But Few Facts.

I don’t know why there is so much misinformation and so much fear being spread about hybrids out there. I wrote Hybrid Cars: The Benefit of My Research (the 2nd link down in the static pages on the bar to the right) to try to distill some of my research over a year ago. Some of that information is starting to get out of date, but I don’t think that anyone has ever read it anyway, so I’m not sure if I should bother updating it with things like this.