California resident Victor Murillo was recently awakened at 3:00 in the morning by a loud metallic thud outside his apartment window. Thinking the sound was made by a garbage truck, he rolled over and went back to sleep. But when he emerged from his apartment to go to work and started up his Toyota Tacoma, the engine sounded like a small volcano erupting. The din was loud enough to wake a neighbor, and while Murillo shut off the truck and wondered what could possibly be making so much racket, the neighbor emerged and delivered bad news.

"I know that noise," he said. "That's the sound of a stolen catalytic converter."

In less than the three minutes it took a thief to unbolt the converter and take off, Murillo was out $250 in theft insurance deductible dollars and had to do without his work truck for the two days it took the local mechanic to install a new unit.

"I wasn't really angry," he told AOL Autos. "I just wanted my truck back."

Catalytic converters, which convert engine pollutants into less harmful emissions before they leave a vehicle's exhaust system, have been mandated on all American cars since 1975. In recent years, however, converter thefts have massively increased as the market for the their precious metals, including trace amounts of palladium, rhodium and platinum, have skyrocketed.

The problem is so acute that California passed a law in January 2010 mandating that recyclers document each converter brought in to be sold for scrap and create a paper trail to deter the theft and resale of the units.

"It has gotten to the point where everyone knows someone who has had their catalytic converter removed illegally from their vehicle", says California Senator Ron Calderon, who wrote the bill. "Stolen catalytic converters fetch between $50-$150 at scrap yards. And yet they cost between $300-$3000 to replace."

The new legislation requires all businesses to document converter sales, their date and locations as well as taking a photo or short video of the seller, and the records must be retained for two years. If you're selling a used converter, the recycler has to pay you by check either mailed to your residence or place of business, or picked up after a three-day delay.

Sound harsh, or Orwellian? Maybe. But since there isn't any method of catalytic converter theft prevention that seems to work, something clearly needed to be done to slow down rings of thieves who drive around all day and night stealing the units. The problem isn't limited to California, either. During the weekend of January 15, 19 cars at a used car dealership in New Jersey were relieved of their converters, and a quick "Catalytic converter stolen" net search reveals similar recent thefts all over the U.S.A. The sloppier crooks can also damage a car's fuel line or wiring, necessitating more costly repairs and inconvenience.

Nationwide Insurance recently published a list of ways motorists can deter converter thieves, including:

- parking your vehicle in well-populated, well-lit areas

- installing conspicuous video surveillance cameras outside homes

- parking your vehicle in a closed, locked garage

- watching local news to monitor epidemics of local converter thefts so as to take extra precautions

- etching the car's VIN number on the converter to make it easier to identify a ring of thieves in the future

Converter etching may sound like overkill, but Senator Calderon doesn't think so, saying, "Some people have had their cars vandalized multiple times and often from their own driveways."

Nationwide also recommend having the converter welded to the frame of your vehicle, but that also brings new issues to deal with.

Murillo, whose Tacoma is one of the most popular targets for thieves due to their easily removable bolted converters, says, "I looked into welding and I found that auto shops can do it around here for about $200, but if you don't pass inspection in the future and need to remove your catalytic converter and/or muffler, you cost yourself even more money because they have to go through the welds just like a thief would."

There are also many aftermarket units meant to deter catalytic converter theft, including the CatClamp which features a stainless steel cable its website claims is "virtually impossible to cut."

Experts aren't so sure, though. "CatClamps are pretty easy to remove," says Popular Mechanics Senior Editor Mike Allen, who has made a career out of testing and praising or debunking aftermarket products. "Especially if you have a 4x4 pickup or SUV that has enough room for the perp to slide under. The cable severs readily with a big bolt cutter or a cordless cutoff wheel."

The best deterrent in the end, Allen says, is "A big Rottweiler chained to the bumper."