Mazda 3 Owner's Manual page 102

Engine Exhaust (Carbon monoxide)
WARNING
Do not drive your vehicle if you smell exhaust gas inside the vehicle:
Engine exhaust gas is dangerous. This gas contains carbon monoxide (CO), which is
colorless, odorless, and poisonous. When inhaled, it can cause loss of consciousness and
death. If you smell exhaust gas inside the vehicle, keep all windows fully open and contact
an Authorized Mazda Dealer immediately.
Do not run the engine when inside an enclosed area:
Running the engine inside an enclosed area, such as a garage, is dangerous. Exhaust
gas, which contains poisonous carbon monoxide, could easily enter the cabin. Loss of
consciousness or even death could occur.
Open the windows or adjust the heating or cooling system to draw fresh air when
idling the engine:
Exhaust gas is dangerous. When the vehicle is stopped with the windows closed and
the engine running for a long time even in an open area, exhaust gas, which contains
poisonous carbon monoxide, could enter the cabin. Loss of consciousness or even death
could occur.
Clear snow from underneath and around your vehicle, particularly the tail pipe, before
starting the engine:
Running the engine when a vehicle is stopped in deep snow is dangerous. The exhaust
pipe could be blocked by the snow, allowing exhaust gas to enter the cabin. Because
exhaust gas contains poisonous carbon monoxide, it could cause loss of consciousness or
even death to occupants in the cabin.
Before Driving
Fuel and Emission
3–29