State of Rhode Island Department ofEnvironmental Management

Office ofAi r Resources In Re: Adoption of the "Providence Carbon Monoxide Limited Maintenance Plan" and amendments to the "Rhode Island Air Pollution Control General Definitions" regulation and to Air Pollution Control Regulations Nos. 9, 11, 22 and 36. DECISION Introduction On 8 July 2008 a notice was published in the Providence Journal-Bulletin and was mailed to interested parties announcing a public hearing and comment period to accept comments on the proposed adoption the "Providence Carbon Monoxide Limited Maintenance Plan" and amendments to the "Rhode Island Air Pollution Control General Definitions" regulation and to Air Pollution Control Regulation Nos. 9, 11, 22 and 36 . The public hearing was held on 8 August 2008 in Room300 ofthe Department of Environmental Management Building, 235 Promenade Street, Providence, Rhode Island. The public comment period extended until 4 :00 PM on 8August 2008. The proposed "Providence Carbon Monoxide Limited Maintenance Plan" specifies measures that will be used by the Rhode Island Department of Environmental Management (RI DEM) to ensure that Providence remains in attainment ofthe National Ambient Air Quality Standard for carbon monoxide through 2011 . The proposed revisions to Regulation No. 11, "PetroleumLiquids Marketing and Storage," would allowgasoline dispensing facilities that exclusively fuel rental cars or corporate or commercial fleets to apply for exemption fromStage II vapor recovery requirements and would require annual testing ofpressure vacuumcaps on Stage II systems. The proposed revisions to Regulation No. 22, "Air Toxics" would update several Acceptable Ambient Levels and Minimum Quantity thresholds in that regulation; add an additional substance, n-propyl bromide, to the list ofregulated air toxics; exempt existing fuel burning sources, including those burning biodiesel, as well as water pollution control systems and small organic solvent cleaning sources; and clarify reporting requirements. The Minimum Quantities listed in Regulation No. 9, "Air Pollution Control Permits," would be changed to be consistent with those in Regulation No. 22. Two guidelines that are referenced in Regulation No. 22, the "Rhode Island Air Toxics Guideline" and the "Rhode Island Guideline forAir Quality Modeling for Air Toxics Sources," would also be updated. The proposed update to the modeling guideline specifies that, henceforth, RI DEM will performonly screening level modeling when evaluating permit applications.The proposed revision to Regulation No. 36, "Control of Emissions fromOrganic Solvent

Cleaning," would exempt cold cleaners using solvents containing 5%or less volatile organic compounds and volatile hazardous air pollutants, clarifywork practice and reporting requirements, regulate vapor cleaners using trans 1,2-dichloroethylene or n-propyl bromide, adopt federal facility-wide emissions limits and establish a vapor pressure limit for solvents used for cold cleaning. The General Definitions regulation wouldbe amended to include definitions consistentwith the proposed updates ofRegulations No. 22 and 36 . Decision It is the decision ofthe Hearing Officerto adopt the proposed "Providence Carbon Monoxide Limited Maintenance Plan" and amendments to the "Rhode Island Air Pollution Control General Definitions" regulation and to AirPollution Control Regulation Nos. 9, 11, 22 and 36, modified as discussed in the response to comments that follows. The final amended regulations andplan are appended to this Decision. 

# '~ 5' Date St~ en Ma3kut, Hearing Officer Approved:

Date 

## r_= W . Michael Sullivan DirectorResponse to Comments

This section will present the Rhode Island Department of Environmental Management's (RI DEM's) response to the comments received at the public hearing and during the public comment period. Each comment has been paraphrased and is followed by RI DEM's response. Similar comments have been grouped together. Alist of commenters is attached. Carbon Monoxide Limited Maintenance Plan Comments Comment: EPA generally agrees with Rhode Island's approach of establishing alternative criteria for identifying potential COproblems in Providence, in lieu of operating a COmonitor. (EPA) Response: No response required. Comment : RI DEM is proposing to use the East Providence photochemical assessment monitoring site (PAMS) as one indicator of a potential carbon monoxide (CO) problemin Providence. In order to be more protective, RI DEM should reestablish COmonitoring in Providence ifthe East Providence design value exceeds 5 ppm, rather than the proposed 6 .5 ppm . 

### (EPA) Response: While RI DEM believes that the method used to derive the 6 .5 ppm Action Level is logical and appropriate, that level has been changed to 5 ppm, as suggested in this comment, in order to be more protective. Note that the current COdesign value at the East Providence site is 1 .6 ppm . Comment : The COemissions trigger for reestablishing COmonitoring in Providence should be strengthened fromthe level corresponding to a 100%increase to the level corresponding to a 30°1o increase in COemissions in Providence County from2002 levels . The COdesign values in 1989-1993 in Providence were approximately equal to 7.65 ppm, the value at which an area is eligible for a limited maintenance plan and COemissions inventories in neighboring states show that COemissions decreased approximately 30% between 1990and 2002. (EPA) Response: The Action Level for COemissions was changed from293,666tons per year (double the 2002 inventory) to 190,883 tons per year (30%higher than the 2002 inventory) in response to this comment.Regulation No. 11 Comments

Comment : Rhode Island should consider also exempting facilities that dispense only E85 fromStage II requirements, as allowed EPA Guidance. (EPA) Response : RI DEM has not identified any facilities in Rhode Island that dispense E85 fuel . RI DEM will consider an exemption forsuch facilities at a future date. The regulation was not changed in response to this comment . Comment : Rhode Island may wish to consider requiring ORVRcompatible Stage II systems. The cost associated with installation of ORVRnozzles and other hardware is between $5,000 and $10,000per station, according to the California Air Resources Board. The incremental cost to new installations would be lower. Such controls should be considered as potential cost-effective control strategies. (EPA) Response: RI DEM is currently participating in an evaluation ofavailable ORVR-compatible equipment in the State and will consider requiring such equipment in future amendments to Regulation No. 11 . The regulation was not changed in response to this comment . Comment : The version of Regulation No. 11 currently approved in the Rhode Island State Implementation Plan (SIP) requires all facilities that dispense greaterthan 10,000 gallons of gasoline per month as well as all gasoline dispensing facilities constructed or substantially modified after 15 November 1992 to install Stage II . However, the existing and proposed version allows a new

or substantially modified facility to request an exemption if it dispenses less than 10,000 gallons per month and demonstrates that Stage II controls are not technically and/or economically feasible. When RI DEM submits this amended version of Regulation No. 11 as a SIPrevision, information on the number and throughput ofstations that have been granted an exemption should be included. (EPA) Response: That information will be included in the SIP submittal . The regulation was not changed in response to this comment. Regulation Nos. 9 and 22 Comments Comment: The proposed amendments to Regulation No. 22will encourage the use of npropyl bromide (nPB) over less toxic solvents liked trans-dichloroethylene (t-DCE) . Adegreaser using between 200and 10,000 pounds peryear ofsolvent would be required to file an annual registration if that solvent is nPB, but not if it is t-DCE. Moreover, the air toxics modeling submitted as part of an Air Toxics Operating Permit would favor nPB over t-DCE, since the Acceptable Ambient Levels (AALs) for nPBare less stringent than those for t-DCE. This isinconsistent with toxicity data submitted to RI DEM, which shows that the rat 90-day inhalation

No Adverse Effects Level (NOAEL) for t-DCE is 4,000 ppm, while that for nPB is 100-200ppm . Moreover, the ACGIHrecommended occupational limits are 200ppm fort-DCE and only 10 ppm for nPB . The ATSDRMinimal Risk Levels and EPARfl)s used as the basis of the Rhode Island AALs for t-DCE were developed in 1996 and 1989 respectively and do not reflect more current toxicity data, which were developed through the EPA's High Production Volume Challenge Programand have been made availableto RI DEM . (3M and PPG) Response: The AALs for t-DCE and nPBwere derived using the methodology specified in the Air Toxics Guideline. In reviewing the AAL for t-DCE, RI DEM has concluded that the RfD could be used as an annual average AALrather than a 24-hour average AAL, since a safety factor to convert subchronic to chronic exposure times was used in the RfDderivation. This would result in an increase in the Minimum Quantity threshold value for that substance from200to 300 pounds peryear. The AALs and Minimum Quantities for t-DCE have been changed in Regulation Nos. 9 and 22 as well as in the twoguideline documents to reflect that adjustment . RI DEM has reviewed the toxicological data for t-DCE provided by the commenters. Those studies, which have not been published in a peer reviewedjournal, indicate that a less stringent interpretation ofthe earlier studies used to develop the EPA and ATSDRhealth benchmarks on which the Rhode Island AALs were based may be appropriate. RI DEM suggests that the new data be made available to those agencies and, ifthe EPAand/or ATSDRhealth benchmarks are updated, RI DEM

will propose corresponding changes to the Rhode Island AALs. In addition, if updated health benchmarks are derived for nPB, RI DEM will update the AALs for that substance accordingly. RI DEM understands that the fact that the AALs for t-DCE are more stringent than those for nPB may cause some facilities to favor nPB over t-DCE. However, as the commenters point out, the more stringent requirements applies only to cleaners using more than 2,000pounds ofsolvent per year, since smaller cleaners are exempt fromRegulation Nos. 9 and 22 and the control requirements in Regulation No. 36 are the same for either solvent. Further, any advantage to using one solvent over the other may disappear in the future ifthe AALs are further revised when new health benchmarks are available. Comment : Change the definition ofnew major fuel burning source in 22.2.2(c) to a source that begins operation as of the effective date or the new regulation, rather than retroactive to 27 April 2004. (ESS) Response: The regulation was not changed in response to this comment. This is not a new specification; new

major fuel burning sources have been subject to Regulation No. 22 since the 2004 amendments.