Vapor Recovery Systems Guide
Understanding Stage I and Stage II vapor recovery systems, compliance requirements by state, and the impact of ORVR (Onboard Refueling Vapor Recovery) on modern requirements.
Stage I
Tanker to Tank - Captures vapors during fuel delivery
Required in most jurisdictions
Stage II
Dispenser to Vehicle - Captures vapors during refueling
Phased out in many states (ORVR waiver)
Stage I Vapor Recovery
Captures vapors displaced from underground storage tanks during fuel delivery from tanker trucks.
How It Works
When fuel flows into UST, vapors are displaced. Instead of venting to atmosphere, vapors flow through a dedicated return line back to the tanker truck for transport to terminal recovery.
Components
- -Vapor return drop tube
- -Vapor recovery adapter (coaxial or dual-point)
- -Vapor-tight fill caps
- -Pressure/vacuum vent valves
- -Vapor return piping
Required Where
- +All 50 states for new installations
- +Ozone non-attainment areas
- +Most urban areas
- +High-throughput stations
Exemptions
- -Some grandfathered rural locations
- -Very low throughput sites (check state rules)
- -Agricultural fueling with exemptions
Stage II Vapor Recovery
Captures vapors displaced from vehicle fuel tanks during refueling at the dispenser nozzle.
How It Works
As fuel enters vehicle tank, vapors are captured by the nozzle boot/bellows and returned through a coaxial hose or dedicated vapor line to the underground tank.
Components
- -Vapor recovery nozzle with bellows/boot
- -Coaxial or dual-hose hanging hardware
- -Vapor recovery vacuum pump (if vacuum-assist)
- -Vapor processor unit
- -Vapor piping within dispenser
Required Where
- +California (CARB mandated)
- +Some northeastern states
- +Severe ozone non-attainment areas
Exemptions
- -States that adopted ORVR waiver (most states)
- -EPA-approved ORVR areas
- -Most of central/southern US
What is ORVR?
Onboard Refueling Vapor Recovery (ORVR) is a vehicle-based system required on all cars and light trucks since 1998-2006. These systems capture fuel vapors in the vehicle's carbon canister during refueling.
The EPA determined that ORVR makes Stage II redundant, leading most states to accept an "ORVR waiver" allowing Stage II decommissioning. This significantly reduces equipment and maintenance requirements for stations.
Frequently Asked Questions
What is the difference between Stage I and Stage II vapor recovery?
Stage I captures vapors when fuel is delivered from a tanker truck to the underground storage tank. Stage II captures vapors when customers refuel their vehicles at the dispenser. Stage I is required nearly everywhere, while Stage II requirements vary by state and have been phased out in many areas due to ORVR (onboard vehicle recovery systems).
Is Stage II vapor recovery still required?
It depends on your state. California still requires Stage II (and Enhanced Vapor Recovery). Most other states accepted the EPA ORVR waiver since modern vehicles (post-1998) have onboard vapor recovery. Check with your state environmental agency. Stage II can often be decommissioned following proper procedures.
What is the difference between balance and vacuum-assist vapor recovery?
Balance systems (passive) use pressure differential to push vapors from the vehicle tank back to the UST - they require a bellows seal at the nozzle. Vacuum-assist systems (active) use a mechanical pump to actively pull vapors, eliminating the need for a tight bellows seal and improving capture efficiency.
What is a P/V vent valve and why is it important?
A Pressure/Vacuum (P/V) vent valve controls underground tank pressure. It opens at specific thresholds (+3 oz pressure, -8 oz vacuum typical) to prevent over-pressure or vacuum damage while keeping the tank sealed during normal operation. This is essential for vapor recovery to work and for emissions compliance.
How do I know if my vapor recovery nozzle needs replacement?
Inspect for: torn or cracked bellows, worn face seals, clogged vapor ports, or latch mechanism failure. If fuel drips excessively, vapors escape during fueling, or customers report difficulty creating a seal, the nozzle likely needs replacement. High-volume sites may need replacement annually.