Is NOS Illegal in Street Cars?

N₂O or Nitrous Oxide is a chemical compound that has a wide range of applications. In the world of street racing, it’s used to temporarily boost performance.

This is done by means of a complex system that routes the gas into the intake manifold which then mixes with fuel and air in the engine.

It’s colloquially referred to as NOS, which is derived from the initials of the company name Nitrous Oxide Systems, Inc.

Nitrous is actually an excellent power adder, especially when you consider the horsepower per dollar ratio.

But then why are nitrous-equipped cars so uncommon? And why are there so many aftermarket superchargers and turbocharger equipped cars?

The simple answer is that N₂O is illegal in many states, but at a federal level in the United States, it is not illegal to install a nitrous kit your car.

Although, each state has its own laws, meaning that while federally legal, your state might still outlaw it.

In this article, we’ve outlined the laws surrounding the use of nitrous oxide as an automotive upgrade, and we’ve listed state-by-state laws.

Nitrous Oxide Car Laws by State

Large NOS cylinder hooked on to a car

Unfortunately, not every state has clear guidelines on the use of nitrous oxide as a power adder in street cars. Many states only reference it in relation to medical and recreational use.

Below we’ve included this data in tabular format; for the states that have unclear laws around the use of nitrous in this application, we’ve included relevant information.

If you happen to live in one of the states where the laws for this are unclear, it is best to contact local law enforcement or the DMV to find out about any possible restrictions.

Even if NOS is legal in your state and if you get pulled over with it, an ill-informed police officer might ticket you if they the kit is clearly visible.

Needless to say, these laws are in reference to whether or not they can be used in street cars; they do not apply to track-driven cars.

StateProhibitionOther Notes
AlabamaUnclear
AlaskaUnclearNo engine modification restrictions
ArizonaUnclearNo engine modification restrictions
ArkansasYesN₂O permitted in if the kit disconnected or canisters are removed
CaliforniaYesIllegal for automotive use
ColoradoYesN₂O permitted in if the kit disconnected or canisters are removed
ConnecticutYesPressurized gases other than natural gas and hydrogen are illegal
DelawareYesN₂O permitted in if the kit disconnected or canisters are removed
District of ColumbiaUnclearDC laws refer to NOS in relation to medicine
FloridaYesPossession of NOS is legal, but the emission of N₂O is regulated
GeorgiaYesN₂O permitted in if the kit disconnected or canisters are removed
HawaiiYesIllegal
IdahoUnclearPossession of NOS is legal, but the emission of N₂O is regulated
IllinoisYesOnly transporting NOS cylinders is permitted, as long as the valves are shut
IndianaNoThere is no law that restricts drivers from using NOS
IowaUnclearNo engine modification restrictions
KansasUnclearNo engine modification restrictions
KentuckyUnclearNo engine modification restrictions
LouisianaYesN₂O permitted in if the kit disconnected or canisters are removed
MaineYesN₂O permitted in if the kit disconnected or canisters are removed
MarylandYesN₂O permitted in if the kit disconnected or canisters are removed. A decal is also required signifying the vehicle contains a flammable cylinder
MassachusettsUnclearMassachusetts requires emissions testing and inspections
MichiganUnclearMichigan only references the legality of NOS for recreational use
MinnesotaUnclear
MississippiYesN₂O permitted in if the kit disconnected or canisters are removed
MissouriUnclearNo engine modification restrictions but some counties require emissions testing
MontanaUnclearNo engine modification restrictions or emissions testing requirements
NebraskaYesIllegal
NevadaUnclearN₂O emissions are regulated
New HampshireUnclearNew Hampshire has no engine modification restrictions but does require emissions testing for vehicles 1996 and newer
New JerseyUnclearNew Jersey only references the legality of NOS for recreational use
New MexicoUnclearNew Mexico requires emissions testing if traveling to Albuquerque 
New YorkUnclearNew York only references the legality of N₂O for recreational use
North CarolinaUnclearEmissions and safety inspections required annually
North DakotaUnclearNo engine modification restrictions or emissions testing requirements
OhioYesNo open NOS containers permitted while driving or while parked in public or publicly accessible areas
OklahomaUnclearOklahoma has no engine modification restrictions or emissions testing requirements in place
OregonUnclearOregon has no engine modification restrictions but some counties require emissions testing
PennsylvaniaYesNOS bottles can only be in vehicle if disconnected from the system
Rhode IslandUnclearNo engine modification restrictions or emissions testing requirements
South CarolinaUnclearNo engine modification restrictions or emissions testing requirements
South DakotaUnclearNo engine modification restrictions or emissions testing requirements
TennesseeYesUse of N₂O in cars is illegal as of 2006
TexasNoNo explicit laws against NOS
UtahUnclearNo restrictions for engine modifications but 3 counties require emissions testing
Vermont UnclearNo engine modification restrictions or emissions testing requirements
VirginiaYesNOS system can be in place as long as it is disconnected and not readily accessible for use
WashingtonUnclearWashington only references the legality of NOS for inhalation
West VirginiaYesCannot drive vehicle on public roads with NOS system unless it is disconnected and not readily accessible
Wisconsin UnclearWisconsin has emission testing required in 7 counties
WyomingUnclearWyoming has no engine modification restrictions or emissions testing requirements in place
Dual chrome NOS canisters installed

In the UK, NOS is legal to use in your car, as long as you report it to your insurance company. Read our guide on modified car insurance to know more about the subject.

In Canada, it is illegal to use NOS on a public road. However, you can have it installed in your car as long as it is disconnected or the canisters are removed.

This is similar to the rule in some states that permits you to have a nitrous kit in your car but it is not street legal.

Concluding Summary: Is It Illegal to Have NOS in Your Car?

RX7 nitrous purge

A lot of the ambiguity around the use of N₂O can be attributed to its medical and recreational use, even though it’s not a controlled substance. Some of the applications include:

  • Analgesic and anesthetic (medical use)
  • Used in whipped cream chargers
  • Used in rocket motors as an oxidizer
  • Semiconductor manufacturing

In most states, as long as the components in your NOS kit have a certification number, it will be legal.

But it’s worth noting that N₂O is extremely flammable and the kit needs to be installed by a seasoned professional. If you get into an accident, that 950psi canister of Nitrous might make the situation a lot worse.

What are your thoughts on nitrous kits in general? Have you ever driven a car with NOS? Let us know by leaving a comment below!

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