United States
         Environmental Protection
         Agency
Office of the Administrator
Washington, DC 20460
Mail Code 1802
          Project  XL  Progress  Report
          Merck  Stonewall  Plant
EPA 100-R-00-010
December 1999
www.epa.gov/reinvent
         On March 16,1995, the Clinton Administration announced a portfolio of reinvention initia-
         tives to be implemented by the U.S. Environmental Protection Agency (EPA) as a part of its
         efforts to achieve greater public health and environmental protection at a more reasonable
         cost. Through Project XL, which stands for excellence and Leadership, EPA enters into
         specific proj ect agreements with public or private sector sponsors to test regulatory, policy,
         and procedural alternatives that will produce data and experiences to help the Agency make
         improvements in the current system of environmental protection. The goal of Proj ect XL is to
         implement 50 proj ects that will test ways of producing superior environmental performance
         with improved economic efficiencies, while increasing public participation through active
         stakeholder processes. As of October 1999,15 XL projects are in the implementation
         phase and 3 5 XL proj ects are under development. EPA Proj ect XL Progress Reports
         provide overviews of the status of XL proj ects that are implementing Final Proj ect Agree-
         ments (FPAs). The progress reports are available on the Internet via EPAs Proj ect XL web
         site at http://www.epa.gov/Project XL. Or, hard copies may be obtained by contacting the
         Office of Reinvention's Project XL general information number at 202-260-7434. Additional
         information on Proj ect XL is available on the web site or by contacting the general informa-
         tion number.

         Background

         Merck & Co., Inc., is a worldwide research-intensive health products company that discov-
         ers, develops, manufactures, and markets human and animal health products. Merck's
         Stonewall Plant near Elkton, Virginia, was established in 1941. The plant employs over 900
         people in a range of pharmaceutical manufacturing (batch processing) activities such as
         fermentation, solvent extraction,
         organic chemical synthesis, and
         finishing operations.

         The Stonewall Plant is located
         within a mile and a half of the
         Shenandoah National Park, a
         Federal Class I air quality area
         under the Clean Air Act (CAA).
         The facility is subj ect to CAA
         requirements to comply with the
         National Ambient Air Quality
Major Milestones
                                     Merck XL Project
                                     Elkton, Virginia
• 	 7 	
August 24, 1995
Merck XL Proposal
Submitted
s
December 15, 1997
Final Proj ect
Agreement Signed
s
February 10, 1998
PSD Permit
Effective
s
Summer 1999
Installation of the
Gas-Fired Boilers
Completed
s
May 2000
Anticipated
Completion of
Natural Gas Supply
to Boilers
	 7 	 •
August 2005
Anticipated Date of
First Stakeholder
Review

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Merck XL Project                                                                          12-31-99
  Standards (NAAQS). As a result of increased industrial activity in the region, Shenandoah National Park has
  experienced substantial air quality degradation and related resource impacts over the past several decades. In
  1990, the Department of Interior published a public notice describing the negative effects of regional industrial
  development on Shenandoah's visibility, streams, and vegetation.

  In order to reduce negative impacts on the Park and improve economic efficiency, Merck initiated an XL
  proj ect with the EPA in 1995. The Merck XL proj ect creates a facilitywide emissions cap for criteria air
  pollutants that will both (1) provide flexibility for the facility to make production changes without obtaining the
  required prior permitting approval and (2) minimize actual emissions. A new Prevention of Significant Deterio-
  ration (PSD) permit, developed through the Merck XL project, provides alternative methods for complying
  with applicable state implementation plan (SIP) rules, New Source Review (NSR) regulations, and certain
  Resource Conservation and Recovery Act (RCRA) provisions relating to air emission controls on hazardous
  waste equipment. The new PSD permit includes a facilitywide cap for total criteria air pollutants and subcaps
  for sulfur dioxide (SO2), nitrogen oxide (NOx), and parti culate matter with a diameter of less than 10 microns
  (PM-10).
  Through the Merck XL project, environmental benefits will be gained by the following.
  • Capping the facility's total emissions of criteria air pollutants at levels 20% below the baseline levels occur-
    ring prior to the XL proj ect; capping SO2 emissions at levels 25% below baseline levels; capping NOx
    emissions at levels 10% below baseline levels (which should reduce ground-level ozone); and capping PM-
    10 emissions at levels approximately equal to baseline levels.
  • Modifying the facility's existing coal-burning power plantto burn natural gas. Replacing coal-fired boilers
    with natural-gas boilers is expected to result in an upfront reduction of 900 tons per year of total criteria air
    pollutant emissions, to virtually eliminate lead emissions, and to reduce the combined emissions of the
    hazardous air pollutants hydrogen chloride and hydrogen fluoride by 65% (47 tons per year). The conver-
    sion to natural gas is  anticipated to cost Merck approximately $ 10 million; the conversion is not required by
    regulations or as a result of operational problems.
  • Choosing to either comply with specific control-technology requirements in future regulations affecting
    criteria air pollutants, or to reduce the facilitywide cap or subcaps by the amount of reductions that would
    have been achieved through such compliance.
  • Implementing a comprehensive monitoring, record keeping, and reporting program that increases in strin-
    gency as  actual emissions approach the cap.
  • Assessing the air quality impact in Shenandoah National Park if volatile organic compound (VOC) emis-
    sions reach specified levels.
  • Ensuring compliance with Significant Ambient Air Concentrations (S AAC) regulations of nonhazardous
    VOC emissions for increases above specified thresholds.

  The Experiment

  The Merck proj ect tests whether the facility can avoid costly production delays while improving environmental
  performance through allowing preapproved operational changes under a sitewide cap on the facility's total
  emissions of criteria air pollutants. The project aims to reduce emission levels for SO2 and NOx, thereby
  protecting visibility and reducing acid deposition in nearby Shenandoah National Park and the neighboring
  community

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 Merck XL Project                                                                          12-31-99
The Flexibility

Merck is working with EPA, the Virginia Department of Environmental Quality (VADEQ), the National Park
Service, and the community to achieve superior environmental performance and to operate the Stonewall Plant
in a more flexible, cost-effective manner. As an incentive to achieving superior environmental performance, EPA
is offering Merck regulatory flexibility in the area of air permitting.

The statutory programs, and the EPA offices administering the programs, that affect the Merck XL proj ect are;
• Clean Air Act (CAA) programs, administered by EPAs Office of Air Quality Planning and Standards;
• Resource Conservation and Recovery Act (RCRA) programs, administered by EPAs Office of Solid Waste;
  and
• Pollution Prevention Act (PPA) programs, administered by EPAs Office of Prevention, Pesticides, and Toxic
  Substances.
EPA has delegated to the Commonwealth of Virginia full authority to implement and enforce the new PSD
permitting program.

Air Quality Permitting. Pursuant to an agreement between EPA and VADEQ, the latter issued a new, unlim-
ited-duration PSD permit for a facilitywide air emissions cap at the Merck Stonewall Plant. The permit defines
compliance with PSD, minor NSR, and other regulatory requirements. A variance issued by VADEQ for the
Stonewall Plant allowed VADEQ to issue the flexible PSD permit. Merck will be required to comply with the
facilitywide emission caps by, at the latest, 12 months after the facility converts its coal-fired boilers to natural-
gas boilers. Until that time, existing air quality permits and regulations, specifically Federal and state PSD and
minor NSR permits and regulations, govern facility operations.

The facility's existing air quality permits require that most changes to manufacturing processes be reviewed and
approved by VADEQ prior to implementation. The complexity of the regulations requires a considerable effort
by the facility and regulators to prepare and review permit applications for many process modifications. Under
the Stonewall Plant's new PSD permit, changes or additions to facility operations that result in emission in-
creases would no longer require prior approval under either Federal or state NSR regulations.

Merck's new PSD permit provides the facility with the flexibility to implement a change in operations that could
increase emissions, within the constraints of the total criteria pollutant cap and the individual pollutant subcaps
for SO2, NOx, and PM-10. In addition, the permit affords Merck the option of reducing the facilitywide caps
instead of implementing specific control technologies prescribed by future regulations. Merck is also provided
flexibility in complying with RCRA air emission requirements that apply to certain existing hazardous waste
management units. This operational flexibility is provided in return for the facility demonstrating ongoing superior
environmental performance resulting from the permanent, substantial reduction of emissions; the conversion of
the power plant to natural gas; the requirements to increase monitoring, record keeping, and reporting as actual
emissions approach the caps; and the establishment of five-year periodic stakeholder reviews.

The variance and permit streamline requirements regarding both the content of application for Merck's Title V
operating permit and the compliance certification. Merck is required to obtain a Title V permit and will continue
to be responsible for adhering to all other applicable state and Federal air regulations. Merck will comply fully
with all applicable requirements for the control of hazardous air pollutants (FLAPs) under CAA section 112,
including;

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Merck XL Project                                                                          12-31-99
  •  maximum achievable control technology (MACT) standards for the pharmaceutical industry under CAA
    section 112(d);
  •  risk management plan requirements under CAA section 112(r); and
  •  future residual risk regulations under CAA section 112(f).
  Environmental Performance Reporting. The Merck project provides an innovative three-tiered approach to
  monitoring, record keeping, and reporting linked to its air quality permit. A site-specific rule and new PSD
  permit, developed through the Merck proj ect, provide alternative methods for complying with applicable SIP
  air quality rules, NSR air emission regulations, and certain RCRA provisions relating to air emission controls on
  hazardous waste equipment. The new PSD permit includes a facilitywide cap for total criteria air pollutants
  and subcaps for SO2, NOx, and PM-10.  The requirements for monitoring, record keeping and reporting
  increase in stringency as the facility's actual total criteria air emissions approach the sitewide emissions cap.
  Annual reporting is required when facilitywide emissions are less than 75% of the cap. Semiannual reporting is
  required when facilitywide emissions are between 75% and 90% of the cap. Monthly reporting is required
  when emissions are equal to or greater than 90% of the total emissions cap. Additionally, monitoring and
  record-keeping requirements for certain processes may range from daily to annually, depending on the facility's
  environmental performance relative to the statewide emissions cap. This provides an incentive for Merck to
  purchase the cleanest available technologies and to maintain low air emission levels.

  Promoting Innovation and System Change

  Proj ect XL provides EPA opportunities to test and implement approaches that protect the environment and
  advance collaboration with stakeholders. EPA is continually identifying specific ways in which XL proj ects are
  helping to promote innovation and system change. The innovations and system changes emerging from the
  Merck XL project are described below.
  LimitedPreapprovals for Air Permits. Certain industries change their product lines frequently. Usually, such
  changes require a time-consuming preconstruction permit exercise. By focusing on the total emissions of a
  facility, XL is testing and confirming flexible emission reduction strategies that may be both duplicated at similar
  facilities across the country and integrated into EPA's existing regulatory regime. Concepts tested by Proj ect
  XL have already been integrated into the national regulatory system. The recent Pharmaceutical MACT
  regulations promulgated in September 1998 have incorporated lessons learned from the Merck FPA, allowing
  the limited preapproval of certain types of production changes without requiring permit revision for each
  modification. The Agency is formally considering further expanding this use of preapproval and "cap permits."
  Tiered Reporting—Building Incentives into Data Collection Requirements. A key innovative feature of
  Merck's XL proj ect i s that the monitoring, record keeping, and reporting requirements for the P SD permit
  increase in stringency as the site's actual total criteria pollutant emissions come closer to the total emissions cap.
  Annual reporting is required when facilitywide emissions are less than 75% of the cap. Semiannual reporting is
  required when facilitywide emissions are between 75% and 90% of the cap. Monthly reporting is required
  when emissions are equal to or greater than 90% of the total emissions cap. This provides an additional incen-
  tive for the facility to minimize its emissions. This proj ect will serve as a test bed for sectorwide collection of
  higher quality information from regulated industries, and will directly influence the Comprehensive Information
  Management Plan being developed by EPA's new consolidated Environmental Information Office.

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 Merck XL Project
                                       12-31-99
Project Commitment Summary
This table and the environmental performance section that follows summarize progress in meeting commitments
described in the FPA for Merck's Stonewall Plant.
  Commitment
 Status
                                      EPA Commitments
  Issue a site-specific rule to provide an alternative
  means of compliance with applicable state SIP rules
  and NSR standards and to address certain provi-
  sions of RCRA air standards for air emission
  controls on hazardous waste equipment.
EPA proposed a site-specific PSD and NSR rule on
March 31,1997, that applies only to Merck's
Stonewall Plant. This rule also addresses the rel-
evant provisions of RCRA air standards for air
emission controls. EPA promulgated the final rule on
Octobers, 1997.
  Issue a site-specific revision to Virginia's SIP that
  delegates authority to the Commonwealth of Virginia
  for implementing and enforcing the site-specific PSD
  rule, and that allows for an alternate means of
  compliance with newly applicable rules.
EPA proposed delegation of authority in the site-
specific rule issued March 31,1997. EPA delegated
full authority to Virginia for implementing and
enforcing the site-specific PSD rule on November
24, 1997.
                            Commonwealth of Virginia Commitments
 Request full delegation of authority for implementation
 and enforcement of the site-specific PSD rule for the
 Merck Stonewall Plant.
 VADEQ requested full delegation from EPA on
 October 27,1997; delegation was granted Novem-
 ber 24,  1997.
 Grant a PSD permit and variance to the Merck
 Stonewall Plant for implementing the XL proj ect.
 On September 11,1997, the State Air Pollution
 Control Board of Virginia issued a variance contain-
 ing site-specific PSD provisions consistent with
 those of EPA's final rule. VADEQ issued the PSD
 permit on January 7,1998, with an effective date of
 February 10,1998.
 Issue a regulation to address EPA's final
 site-specific PSD rule.
 The State Air Pollution Control Board of
 Virginia approved a regulation that incorporated by
 reference the provisions of EPA's final site-specific
 PSD rule on October 1, 1997.

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Merck XL Project
                                      12-31-99
  Commitment
 Status
                                 Merck & Co., Inc. Commitments
  Replace coal-fired boilers with natural gas boilers
  that can use distillate oil as backup fuel.
The new natural gas-fired boilers were installed
during the summer of 1999, and will be fired when
the natural gas supply to the equipment is com-
pleted. At one point, the conversion was anticipated
to be complete in June 1999; however, the arrange-
ments for a gas line took more time than expected.
Now, completion of the new gas supply is antici-
pated in the spring of 2000. Conversion is still
anticipated for completion before the August 2000
deadline in the PSD permit.
  Implement a three-tiered system for monitoring,
  record keeping, and reporting.
The three-tiered monitoring, record keeping, and
reporting requirements will become effective no later
than 12 months after boiler conversion is completed.
  Submit emission reports to all FPA signatories.
Semiannual reports required under the permit are
scheduled for submission by March 1 and
September 1 of each year, beginning in March 2001
(this start date is based on the anticipated completion
date of the boiler conversion).
  Provide XL progress reports to stakeholders
  annually upon initiation of operation of the natural
  gas boilers.
Annual reports required under the permit are sched-
uled for submission by March 1 of each year, begin-
ning in March 2001 (this start date is based on the
anticipated completion date of the boiler conversion).
  Conduct stakeholder meetings to evaluate project
  effectiveness.
Meetings are to be conducted every 5 years begin-
ning within 3 months of the 5-year anniversary of
completion of the boiler conversion.
  Environmental Performance

  This section summarizes progress in meeting the environmental performance described in the FPA for Merck's
  Stonewall Plant. Detailed technical specifications are set forth in the new PSD permit issued by VADEQ.
  The total criteria pollutant and individual criteria pollutant emissions caps will be adjusted downward after boiler
  conversion is complete. Compliance with emission caps will be determined monthly, on a 12-month rolling total
  basis. Boiler conversion will significantly reduce criteria pollutant emissions and, therefore, will immediately reduce
  the 12-month rolling total. However, the 12-month rolling total will not be decreased below the emissions caps for
  some months following boiler conversion. Therefore, the new PSD permit's emission caps may not be enforceable
  until 12 months after boiler conversion is complete. Merck has the option of accepting the provisions of the new
  PSD permit and operating under the caps before this date. As soon as Merck begins operating under the
  emissions caps, they will be allowed to make changes to their processes that result in air emissions increases
  without prior approval, as long as they remain below the caps. Additionally, once the caps are in effect, the
  Stonewall Plant will be required to operate under the caps and increase the frequency of their monitoring, record
  keeping, and reporting if the 12-month rolling total of criteria pollutant emissions triggers the more frequent data-
  collection requirements.

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 Merck XL Project
                                    12-31-99
Air Emissions of Total Criteria Pollutants: The Merck
facility's total emissions of criteria pollutants (including all
criteria pollutants except lead, which will be virtually eliminated
by conversion to the natural gas boiler) will be capped below
the level found to be representative of recent plant operations.
The facility's actual emissions averaged over 1992 and 1993
provide a baseline level of 1,503 tons per year for total criteria
pollutants. Under the new facility wide cap, total criteria pollut-
ant emissions will be maintained at levels below 1,202 tons per
year (a 20% reduction). Merck estimates that up to 2,700 tons
per year would be allowable at its facility under current regula-
tory standards.
                 Total Criteria Pollutants
   Emissions
      Cap
    Baseline
  (1992-1993)
 Standard Permit
    (estimate)
1,503
                        Tons per Year
Progress: Following completion of the boiler conversion, facilitywide air emissions will be determined monthly.
Progress in maintaining total criteria pollutant air emissions at levels below the new cap will be reported in permit-
ting documentation and semiannual reports to FPA signatories.
Air Emissions of Sulfur Dioxide (SOJ: The facility's
actual SO2 emissions averaged over 1992 and 1993 provide a
baseline level of 719 tons per year. The facility's PSD permit
includes a facilitywide cap that limits SO2 emissions following
boiler conversion to 539 tons per year. The cap guarantees a
minimum 25% reduction in SO2 emissions as a result of the
boiler conversion.
Progress: Following completion of the boiler conversion, air
emissions will be determined monthly. Progress in maintaining
SO2 air emissions at levels below the new cap will be reported
in permitting documentation and semiannual reports to FPA
signatories.
Air Emissions of Nitrogen Oxides (NOJ: The facility's
actual NOx emissions averaged over 1992 and 1993 provide
a baseline level of291 tonsperyear. The facility's PSD
permit includes a facilitywide cap that limits NOx emissions
following boiler conversion to 262 tons per year. The cap
guarantees a minimum 10% reduction in NOx emissions as a
result of the boiler conversion.
Progress: Following completion  of the boiler conversion, air
emissions will be determined monthly. Progress in maintaining
NOx air emissions at levels below the new cap will be
reported in permitting documentation and semiannual reports
to FPA signatories.
                   Sulfur Dioxide
 Emissions
    Cap
  Baseline
(1992-1993)
                       Tons perYear
                  Nitrogen Oxides
  Baseline
(1992-1993)
                         150
                      Tons perYear

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Merck XL Project
                                                                                       12-31-99
                                                                     Particulate Matter-10
                                                       Emissions
                                                          Cap
                                                        Basehne
                                                      (1992-1993)
                                                                           Tons per Year
Air Emissions of Particulate Matter (PM-10): The
facility's actual emissions of PM-10 provide abaseline
level (1992 and 1993 average) of 42 tons per year.
Significant decreases in PM-10 emissions are not antici-
pated as a result of the boiler conversion because strin-
gent PM-10 emission controls have already been placed
on the coal-fired power plant. The PM-10 cap initially
will be placed at the baseline level of 42 tons per year.
Following conversion of the power plant to natural gas,
the new boiler will be tested to determine emission levels
at full capacity. So that the new gas-fired boilers can
generate at their full capacity, there will be an automatic
increase in the PM-10 cap of one to  10 tons per year to
account for condensable PM-10 emissions. The cap on total criteria emissions will not be affected by this
automatic increase in the PM-10 cap.
Progress: Following boiler conversion, air emissions will be determined monthly. Progress in maintaining PM-
10 air emissions at levels below the new cap will be reported in permitting documentation and semiannual
reports to FPA signatories.
Hazardous Waste Management Unit Emissions: The Merck PSD permit contains requirements for
compliance with RCRA provisions on the control of air emissions from certain hazardous waste management
units.

Progress: Compliance with hazardous waste management unit emission regulations is being maintained during
conversion of the boiler. The requirements of these regulations will be replaced by alternative provisions
contained in Merck's PSD permit after boiler conversion. Among these requirements: to control select units
with a secondary brine condenser or thermal oxidizer, to continue the maintenance and repair program for
equipment components that are in contact with VOCs, and to maintain and monitor specified covers on
containers and hazardous waste treatment tanks.

Stakeholder Participation

The organizations directly involved in negotiating the FPA included Merck & Co., Inc., EPA, U. S. Department
of the Interior National Park Service, VADEQ, Rockingham County Board of Supervisors, and private
citizens. In addition to the efforts of the EPA and VADEQ to solicit and respond to public comments on the
site-specific rule and variance issued as part of the proj ect, Merck worked to ensure that stakeholders were
involved in the planning of the XL proj ect and were provided opportunities to participate in proj ect develop-
ment. Public meetings were held on
• May 23,1996, at the Merck facility in Elkton, Virginia, to discuss development of Merck's proposed XL
  project and anticipated activities. The meeting was attended by approximately 30 people representing
  government, environmental, and community groups;
• February 27,1997, in Harrisonburg, Virginia, to solicit comment on VADEQ's proposed PSD permit and
  variance. The meeting was attended by 30 to 50 people representing government, environmental, and
  community groups; and

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 Merck XL Project                                                                        12-31-99
•  April 14,1997, in Harrisonburg, Virginia, to solicit comment on EPA's proposed site-specific rule. The
   meeting was attended by 30 to 50 people representing government, environmental, and community groups.
A working committee of government and nongovernment stakeholders was established after the initial public
meeting. The group met weekly for 7 months and frequently thereafter during FPA negotiations. Environmental
organizations offering input during the stakeholder process included the Southern Environmental Law Center,
the Virginia Consortium for Clean Air, and the Natural Resources Defense Council. Stakeholder concerns
expressed during FPA negotiations included minimal opportunities for nonsignatory parties to participate in the
proj ect, shifting of risks associated with exchanging one type of pollutant for another, and the need to clarify
VOC emission issues.

The PSD permit provides that nonsignatory stakeholders, including up to three community representatives and
up to one representative from a regional public interest group, may be designated to participate in project
implementation and review. These stakeholders would receive information and have the opportunity to partici-
pate in the periodic reviews of performance as described in the permit. The permit provides for a review of
certain issues every 5 years and other reviews when specified emission levels are reached. The Merck XL
proj ect stakeholder group will convene every 5 years to evaluate the proj ect's implementation and to mutually
agree on whether project changes are needed.

On an ongoing basis, stakeholders will receive information to enable them to evaluate Merck's performance
under the facilitywide emission caps. This will ensure that local stakeholders are well informed about facility
operations and the impact of incentives to minimize facility emissions. Merck has discussed the proj ect's
progress with interested parties, including employees; Merck retirees; surrounding communities; local, state, and
Federal government officials; and others that expressed interest in the proj ect.

Six-Month Outlook

The key focus area for continued successful implementation of the FPA over the next six months will be to
complete the natural gas supply to the new boilers.

Project Contacts

•  Tedd Jett, Merck &  Co., Inc., (540) 298-4869.
•  Kathleen Henry, EPA Region 3, (215) 814-2175.
•  Christi Gordon, U. S. Department of the Interior, National Park Service, (540) 999-3499.
•  John Daniel, VADEQ, (804) 698-4311.
•  William O'Brien, Rockingham County Board of Supervisors, (540) 564-3000.

Information Sources

The information sources used to develop this progress report include (1) discussions during a teleconference
among representatives  of the Federal and state regulatory agencies, Merck Stonewall Plant, and local stake-
holders involved in the proj ect; (2) the FPA for the Merck XL proj ect; (3) a PSD permit issued by the Com-
monwealth of VA DEQ; (4) a report prepared by Merck & Co., Inc., Merck Project XL PSD Permit Sup-
port Document; and (5) a brief proj ect update from Merck dated August 28,1999. The information sources
are current through August 1999.

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       Merck XL Project                                                                          12-31-99
         Glossary
         Baseline: The measure by which future environmental performance can be compared.

         Class I Air Quality Area: Under the CAA, a Class I area is one in which visibility is protected more stringently
         than under the NAAQS. These areas include national parks, wilderness areas, monuments, and other areas of
         special national and cultural significance.

         Clean Air Act (CAA): The CAA is the comprehensive Federal law that regulates air emissions from area,
         stationary, and mobile sources. This law authorizes the U. S. EPA to establish National Ambient Air Quality
         Standards (NAAQS) and other regulations to protect public health and the environment.

         Condensable PM-10 Emissions: Particulate matter with an aerodynamic diameter less than or equal to a
         nominal 10 microns which are condensed in a filter at ambient conditions.

         Control Technology: Equipment, processes, or actions used to reduce air pollution. The extent of pollution
         reduction varies among technologies. In general, control technologies that do the best j ob of reducing pollution
         are required in areas with the worst pollution. For example, the best available control technology will be
         required in serious nonattainment areas for particulate matter, a criteria air pollutant. A similar high level of
         pollution reduction will be required by MACT regulations for sources releasing HAPs.

         Criteria Air Pollutants: The CAA requires EPA to set NAAQS for certain pollutants known to be hazardous to
         human health. EPA has identified and set standards to protect human health and welfare for six criteria air
         pollutants—ozone (O3), CO, particulate matter, SO2, lead, and NOx. EPA must describe the characteristics
         and potential health and welfare effects of these pollutants. It is on this basis that NAAQS are set or revised.

         Emissions Cap: A provision designed to prevent proj ected growth in emissions from a facility's existing and
         future operations from a specified limit. Generally, such provisions require that emission increases from one
         operation be offset by reductions at other operations at the facility, under the same cap.

         Final Proj ect Agreement (FPA): The FPA outlines the details of the XL project and each party's commitments.
         The project's sponsors, EPA, State agencies,  Tribal governments, other regulators, and direct participant
         stakeholders negotiate the FPA.

         Hazardous Air Pollutants (HAP): Air pollutants that are not covered by NAAQS, but that may present a threat
         of adverse human health effects or adverse environmental effects. Examples of such pollutants include asbes-
         tos, beryllium, mercury, benzene, coke-oven emissions, radionuclides,  and vinyl chloride.

         Hazardous Waste Management Unit: A contiguous area of land on which hazardous waste is placed, or the
         largest area in which there is significant likelihood of mixing hazardous waste constituents in the same area.

         Hydrogen Chloride: A colorless, pungent, poisonous gas that yields hydrochloric acid when dissolved in water.

         Hydrogen Fluoride: A colorless, corrosive gas that yields a hydrofluoric acid when dissolved in water.

         Maximum Achievable Control Technology (MACT): The emission standards for sources of HAPs requiring
         the maximum reduction of hazardous emissions, taking cost and feasibility into account. Under the CAA
         Amendments of 1990, the MACT standards must not be less than the average emission level achieved by
         controls on the best-performing 12% of existing sources, by category.

         Media: Specific environments-air, water, soil-which are the subject of regulatory concern and activities.

         Multi-media: Several environmental media, such as air, water, and land.

10

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 Merck XL Project                                                                          12-31-99
National Ambient Air Quality Standards (NAAQS): Regulations promulgated by EPA under the CAA for
six criteria pollutants—SO2, particulate matter, NOx, CO, ozone, and lead—in order to protect the public
from the impacts of these atmospheric emissions.
New Source Review (NSR): TheNSR and Prevention of Significant Deterioration (PSD) provisions of
the CAA strive to ensure that potential new sources of air pollution (new plants or facilities, or additions to
existing ones) take proper steps to minimize pollution levels. The goals of the NSR program are (1) to
ensure that an increase in emissions due to a new source or modification to an existing source does not
significantly deteriorate air quality; (2) to ensure that source emissions are consistent with applicable state
attainment plans; and (3) to establish control technology requirements that maximize production capacity
while minimizing air-quality impacts.
Nitrogen Oxides (NOx): An air pollutant that is the result of photochemical reactions of nitric oxide in
ambient air. Typically, it is a product of combustion from transportation and stationary sources. It is a
major contributor to the formation of ozone in the troposphere, photochemical smog, and acid deposition.
Ozone (O3): Ozone is found in two layers of the atmosphere, the stratosphere and the troposphere. In the
stratosphere (the atmospheric layer 10 miles or more above the earth's surface), ozone is a natural form of
oxygen that provides a protective layer shielding the earth from ultraviolet radiation. On the other hand, in
the troposphere (the layer extending up to 10 miles from the earth's surface), ozone is a maj or component
of photochemical smog. It can seriously impair respiratory systems and is one of the most widespread of
all the criteria pollutants. Ozone in the troposphere is produced through complex chemical reactions
involving NOx, VOCs, and sunlight.
Parti culate Matter: Fine liquid or solid particles, such as dust, smoke, mist, fumes, or smog, found in air or
emissions.
PM-10:  Parti culate matter with a diameter of less than 10 microns.
Pollution Prevention Act (PPA): The PPA focuses on enhancing industry, government, and public attention
on reducing the amount of pollution through cost-effective changes in production, operation, and raw-
materials use. Pollution prevention includes practices that increase efficiency in the use of energy, water, or
other natural resources, and that protect resources through conservation. These practices include recy-
cling, source reduction, and sustainable agriculture.
Precursor: In photochemistry, a compound antecedent to a pollutant. For example, VOCs and NOx often
react in sunlight to form ozone. As such, VOCs and NOx are precursors to ozone.
Prevention of Significant Deterioration (PSD): The part of the NSR program in which state or Federal
permits are required to restrict emissions for new or modified sources in locations where air quality already
attains ambient air quality standards.
Resource Conservation and Recovery Act (RCRA): RCRA gives EPA the authority to control hazardous
waste from the "cradle-to-grave." This includes the generation, transportation, treatment, storage, and
disposal of hazardous waste. RCRA also set forth a framework for the management of nonhazardous
wastes and underground storage tanks. RCRA focuses only on active and future facilities and does not
address  abandoned sites.
Significant Ambient Air Concentrations (SAAC): Regulations promulgated by the Commonwealth of
Virginia under the State Air Pollution Control Law to protect the public from emissions of non-criteria air
pollutants.
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         State Implementation Plans (SIP): EPA-approved state plans for the establishment, regulation, and enforce-
         ment of air pollution standards.

         Sulfur Dioxide (SO2): Sulfur dioxide gases are formed when fuel containing sulfur (mainly coal and oil) is
         burned during metal smelting and other industrial processes. Sulfur dioxide is associated with acidification of
         lakes and streams, accelerated corrosion of buildings and monuments, reduced visibility, and adverse health
         effects, including effects on breathing, respiratory illness, and aggravation of existing cardiovascular disease.

         Thermal Oxidizer: An enclosed device that destroys organic compounds by thermal oxidation, i.e. reacting at
         elevated temperatures with oxygen.

         Title V of the Clean Air Act: Title V establishes a Federal operating permit program that applies to any maj or
         stationary facility or source of air pollution. The purpose of the operating permits program is to ensure
         compliance with all applicable requirements of the C AA. Under the program, permits are issued by states or,
         when a state fails to carry out the CAA satisfactorily, by EPA. The permit includes information on which
         pollutants are being released, how much may be released, and what steps the source's owner or operator is
         taking to reduce pollution, including plans to monitor the pollution.

         12-month Rolling Total Basis: The 12-month rolling total for an individual pollutant is calculated on a monthly
         basis as the sum of all actual emissions of the respective pollutant from the previous 12 months.

         Variance: Government permission for a delay or exception in the application of a given law, ordinance, or
         regulation.

         Virginia State Air Pollution Control Board: A regulatory board, composed of Virginia citizens appointed by
         the Governor, which is responsible for oversight of the adoption of Virginia's environmental air quality regula-
         tions. The board has statutory authority to promulgate regulations and to approve certain permits. Before
         promulgating regulations required by environmental statutes, the board seeks information from the public, the
         regulated community and advisory committees.

         Volatile Organic Compound (VOC): Any organic compound that evaporates easily into the atmosphere and
         that participates in atmospheric photochemical reactions, except for those compounds designated by the
         EPA Administrator as having negligible photochemical reactivity. VOCs are a precursor to the formation of
         the total criteria air pollutant ozone, and as such, are subj ect to regulation under the NAAQS. VOCs also
         may be HAPs that are subj ect to regulation under the MACT standards.
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