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Stage-Two (II) Vapor Recovery in Vermont

In August of 1996, the Air Quality & Climate Division adopted rule 5-253.7 (Stage II Vapor Recovery Controls at Gasoline Dispensing Facilities) to help prevent the release of harmful gasoline vapors to Vermont's ambient air. The requirements of the rule apply to any gas station with an annual gasoline throughput of 400,000 gallons or more.

Not only do gasoline vapors contain several known and suspected human carcinogens, there are also several noncarcinogenic hazardous air contaminants in gasoline vapor. Many of those same toxic chemicals are ground-level ozone precursors as well i.e., they are the chemicals that under the right atmospheric conditions (the presence of sunlight and warm, summer-time temperatures) react to form ground-level ozone, a strong lung and eye irritant known to trigger asthma.

The Vermont Air Quality & Climate Division encourages you to choose gasoline stations with vapor recovery nozzles. These gasoline nozzles have prevented several thousand tons of volatile organic compounds from evaporating into Vermont's air during the past several years. Please remember not to top off your gas tank. "Topping off" or continuing to fill your tank after the pump clicks off may result in gasoline spillage or block the vapor recovery system, rendering it ineffective. Generally, when the pump shuts off, your tank is full and topping-off adds only a few more ounces.

How to Identify a Gas Station with Stage II Vapor Recovery

In most cases, it should be evident whether a gasoline station has Stage II Vapor Recovery in place. Many stations in compliance with the rule have this blue decal posted at the pump. Often the decals are affixed visibly to the pump near the hook. Also, many vapor recovery nozzles have a "Do not top off" warning printed on the back of the nozzle.

Types of Stage II Vapor Recovery Nozzles

There are three basic nozzle types a person might see at gasoline stations in Vermont.

  • Standard, non-Stage II nozzles
  • Vapor Balance Recovery Nozzles and
  • Vacuum-assist Vapor Recovery Nozzles

Standard Nozzles

Standard nozzles should be found only at gasoline stations (and other gasoline distribution facilities) with a throughput less than 400,000 gallons per year. On the surface, a typical standard nozzle looks very similar to a vacuum assist nozzle but it does not capture gasoline vapors.

Vapor Recovery - Balance Nozzles

Balance system nozzles look distinctly different than standard nozzles. The balance nozzles have a bellows-like rubber boot that creates a seal over the vehicle's gas tank opening. Balance systems use the slight amount of pressure that is created in a vehicle fuel tank by the incoming liquid gasoline and the slight vacuum created in the underground storage tank by the departing liquid gasoline to pull the vapors out of the vehicle tank and transfer them to the underground storage tank. Balance systems require the tight seal of a boot on the nozzle with the vehicle fill-pipe so that the vapors generated during fueling are captured by the nozzle and cannot escape to the atmosphere. The rubber boot must be compressed to activate the pump.

Vapor Recovery - Vacuum-assist Nozzles

Most vacuum-assist nozzles are virtually indistinguishable from nonvapor recovery nozzles. However, many of them have holes near the tip of the nozzle which permits the vapors to be drawn back into the underground gasoline storage tank. The nozzles may have a  small rubber boot or splash guard as well. 

Vacuum-assist systems utilize some type of vacuum producing device (e.g. vapor pump) to enable the nozzle to capture vapors from the vehicle fuel tank. This design allows vapors to be captured without the need for a tight seal by the nozzle boot. 

For further information regarding the Stage II regulation in Vermont please click here. To see subchapter 5-253.7 of the Vermont Air Quality & Climate Regulations click here.

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Last Updated: 1/22/03

 

   
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