Why catalytic converters are being increasingly stolen

It is increasingly common for the catalytic converters on cars to be stolen. This is because the precious metal that forms a key element of the converters has become more expensive. That element is a rare one called rhodium which is, by weight, reportedly the most expensive element on the planet, beating out gold and silver and other precious metals. It is one of the rarest, just one part in a billion, compared with 5% for iron.

The converter on regular fuel vehicles is simple: a stainless steel shell surrounds a ceramic honeycomb monolith— that monolith is coated with three important precious metals: platinum, palladium, and rhodium. 

As the car’s exhaust passes through this honeycomb the metals heat up and act as catalysts: turning carbon monoxide into carbon dioxide, unburned hydrocarbons to H20 and C02, and nitrous oxides into nitrogen and Carbon-dioxide.  

Because these metals, and especially rhodium are so stable and durable they can perform this function over an extremely long lifetime of the car part—suffering very little loss in performance.

So why has the price of rhodium spiked, reaching a peak in March of this year? You guessed it, the pandemic.

Closed mines and refineries created a huge deficit in rhodium, palladium, and platinum supply even as demand was increasing around the world

And if car manufacturers can’t buy these metals from mines—they’ll get it somewhere else: recycling.

Recycled platinum group metals account for a large portion of the precious group metals used by American car manufacturers, which means it’s big business.  That business translates to opportunity on the street:

They’re no longer crimes that are violence, they’re no longer crimes against persons which pulls them from the violent crime status to a property crime. Resources can’t be put to the property crimes like they’re being given attention to the violent crimes. And without specific markings on the catalytic converters themselves there’s no way to determine if Cat 1 vs Cat 2 came off of your car or someone else’s car.

Hybrid cars apparently run at lower temperatures and thus use more rhodium, making them a prime target. At one time, the Toyota Prius was targeted because apparently its converters were easy to remove. But more recently the high prices have made it worthwhile for thieves to target other cars as well.


  1. says

    That’s kind of a weird car-part to steal…”I gotta steal a catalytic converter ‘cuz I want my car to smell like farts whenever it’s running too!”

  2. naturalistguy says

    It isn’t just property crimes that are increasing, as carjackings across the U.S. have doubled in the past year. Why? Because it’s gotten harder to steal unoccupied cars due to improved anti-theft technology, and the fact that as the prices of used cars have soared it’s created a demand for used car parts that are removed from carjacked cars and sold on the parts black market, including catalytic converters.

  3. garnetstar says

    Rhodium (along with palladium) is one of the most-used metals in all kinds of catalysis, including big industrial processes that make things like soap, detergents, inks, plastics, and all kinds of consumer goods.

    And yeah, it’s scarce, recycling the limited supply was inevitable, although not recycling-by-theft.

    Electric cars. Not only do they not need catalytic converters, gasoline is really bad for you (as a chemical, not just a fire-and-explosion hazard). But then, lithium will become even more scarce than it is now, prices will skyrocket, probably a big industry will spring up to recycle it in, um, *creative* ways.

  4. Sunday Afternoon says

    Just today at work I saw a chart presenting the price of Rh as a function of time. It’s very clear why we’re exploring alternative elements…

  5. lorn says

    Things change. I remember when getting decent sound in a vehicle meant buying a massively overpriced aftermarket setup and either paying someone to do it for you or spending a long afternoon messing with it. Thing was aftermarket systems were prime targets for thieves. I used to see enterprising young men on street corners hawking the previous night’s plunder. More that one person was able to buy back their own stolen equipment. A decade later the carmakers started installing high quality units at the factory. It wasn’t that presence of high quality units that ended car stereo theft. It was the simple fact that you couldn’t easily buy a car without one installed. So … no market for stolen radios.

    Catalytic converters have been off and on the plunder lists for decades. Waaay back platinum prices spiked and there was a small wave of thefts. And. of course, any economic downturn might trigger thefts.

    One aspect most people don’t think of is how changes in tool technology effect this sort of thing. Back in the 80s extracting a catalytic converter was hard work. A mechanic might put the car on a lift, hang a work light, plug in a portable band-saw and cut one out in a couple of minutes. The same thing in someone’s driveway with a much tighter space and a manual hacksaw starts to resemble actual work.

    Your modern thief has access to high-performance battery-powered tools. A compact but powerful reciprocating saw powered by lithium-ion batteries can cut through a stainless-steel exhaust pipe in seconds.

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