April 5, 2013

Sent Via Electronic and First Class Mail

Ms. Andrea Siefers

Environmental Engineer, Refining and Chemicals Group

U.S. EPA – Office of Air Quality Planning and Standards 

109 T.W. Alexander Drive, Mail Code: E143-01

Research Triangle Park, NC 27711

Siefers.Andrea@epa.gov

RE: Clarification on Certain Provisions in the National Emission Standards for

Hazardous Air Pollutants for Polyvinyl Chloride and Copolymers 

Production (“PVC MACT”)

Dear Ms. Siefers:

As previously discussed with you and other U.S. Environmental Protection 

Agency (“EPA” or “Agency”) staff, the Vinyl Institute PVC MACT Working Group 

(hereinafter, “Working Group”) has been developing a list of questions relating to the 

implementation of the PVC MACT.1 Although these issues do not appear to require 

substantive revisions to the rule, they do cause confusion about the appropriate 

interpretation of the regulatory language, raise critical questions about how to 

implement the rule, and have the potential to adversely affect compliance within the 

industry. Accordingly, the Working Group requests that the Agency take steps to 

address these issues, either by making minor corrections to the final rule or by providing 

written clarification in a guidance document. These issues are organized by area of 

regulation and generally in the order they appear in the final rule, as follows. 

I. Storage Vessels (77 Fed. Reg. 22,910–11, 22,942; codified at 40 C.F.R. §

63.11910, Table 3) 

The Working Group requests clarification of the venting requirements for fixed 

roof storage vessels in HAP service. The plain language of Table 3 requires venting

certain fixed roof storage vessels in HAP service – those with a capacity greater than or 

 1 In addition to Vinyl Institute (“VI”) members Formosa Plastics Corporation, U.S.A., Occidental Chemical 

Corporation/Oxy Vinyls, LP, PolyOne Corporation, Shintech Inc., and Westlake Chemical Corporation, the 

PVC MACT Working Group has included non-VI members The Dow Chemical Company and Axiall 

(formerly Georgia Gulf) Corporation. The Vinyl Institute, Inc., founded in 1982, is a U.S. trade association 

representing the leading manufacturers of vinyl, vinyl chloride monomer, vinyl additives and modifiers, 

and vinyl compound materials.
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equal to 20,000 gallons, but less than 40,000 gallons, and that contain HAP with vapor 

pressure greater than or equal to 4 pounds per square inch absolute (“psia”) – to a 

closed vent system and 95% efficient control device.2 Currently, however, some fixed 

roof storage vessels are vented back to a closed process in order to maximize recovery 

of vinyl chloride, rather than directly to a closed vent system and control device. 

Interestingly, Table 3 imposes what we presume are even more stringent 

requirements for pressure vessels under higher levels of pressure. Specifically, any 

pressure vessel containing materials at a vapor pressure greater than 11.1 psia must 

comply with the requirements of 40 C.F.R. § 63.11910(c), which provides, in relevant 

part, that:

(1) Whenever the pressure vessel is in hazardous air pollutants 

(HAP) service, you must operate the pressure vessel as a closed 

system that does not vent to the atmosphere, e.g., during filling, 

emptying and purging. The vent stream during filling, emptying and 

purging must meet the requirements of § 63.11925(a) and (b).

Of relevance here, Sections 63.11925(a) and (b) impose requirements on process 

vents, and venting from fixed roof vessels back to the process is a conservative 

approach of managing such vessels. Accordingly, the Working Group asks that EPA 

confirm that this means of handling vapor streams from fixed roof tanks is acceptable. 

One approach could be to revise the language in Table 3 as follows:3

TABLE 3 TO SUBPART HHHHHHH OF PART 63—SUMMARY OF CONTROL REQUIREMENTS FOR STORAGE VESSELS AT

NEW AND EXISTING SOURCES

If the storage vessel capacity (gallons) is . . . And the vapor pressure (psia) is . . . Then, you must use the following type of storage 

vessel . . .

≥20,000 but <40,000 ≥4

Internal floating roof, external floating roof, or 

fixed roof vented to a closed vent system and 

control device achieving 95 percent reduction or 

routed to the process.

≥40,000 ≥0.75

Internal floating roof, external floating roof, or 

fixed roof vented to a closed vent system and 

control device achieving 95 percent reduction or 

routed to the process.

Any capacity. >11.1 Pressure vessel.

All other capacity and vapor pressure combinations Fixed roof.

 2 The Working Group assumes that the 95% reduction required in Table 3 refers to total organic HAP, as 

determined using the procedure described in the definition of “in HAP service.”

3 Internal footnotes omitted.
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II. Equipment Leaks

A. Reciprocating Pumps, Rotating Pumps, and Similar Equipment (77 Fed. 

Reg. 22,911–12; codified at 40 C.F.R. § 63.11915) 

The Working Group submits that the equipment leak provisions in Section 

63.11915 are unclear with regards to the portions of Part 63, Subpart UU that are 

applicable to the various types of equipment within the PVCPU. Consequently, the 

Working Group seeks clarification on the Subpart UU requirements applicable to 

pumps, compressors, agitators, and other equipment under Section 63.11915. In part, 

this confusion arises from changes made to these requirements in the final rule. As 

EPA noted in the preamble to the final PVC MACT rule:

The proposed requirement that reciprocating pumps, reciprocating 

and rotating compressors and agitators be equipped with double 

seals, or equivalent, was in error. In the final rules, we have 

adopted the MACT floor level of control for equipment leaks for 

all components (which is compliance with 40 CFR part 63, 

subpart UU), which gives affected sources the option of installing 

double seals, or equivalent, or complying with the LDAR 

requirements of the equipment leak standards.4

 (Emphasis added.)

As currently written, however, Section 63.11915 creates significant confusion about the 

scope of coverage of Subpart UU. Specifically, the Working Group is confused by the 

departure from the Subpart UU segregation of certain equipment, including pumps, on 

the basis of whether they are in light or heavy liquid service. The exclusion of Subpart 

UU, Section 63.1026, is particularly problematic because most pumps in a PVCPU 

operate in light liquid service. In addition, Section 63.11915(a) expressly excludes a 

reference to Subpart UU for agitators from Section 63.11915(a) and this presents 

problems for certain PVCPUs.

To make matters worse, Section 63.11915 appears to be circular, as it expressly 

states that “[f]or each type of equipment specified in paragraphs (b)(1) and (2) of this 

section, you must also meet the requirements of paragraph (a) of this section,” meaning 

compliance with Subpart UU. In addition, both Sections 63.11915(b)(1) and (b)(2) state 

that for rotating pumps, on the one hand, and reciprocating pumps, rotating 

compressors, reciprocating compressors, and agitators, on the other, compliance may 

be achieved “by complying with the requirements of 40 CFR part 63, subpart UU for the 

relevant equipment.”

 In our view, the inclusion of this language in subparagraphs (b)(1) and (b)(2) is 

redundant, because the option to use double mechanical seals or sealless pumps is 

already provided for pumps in Sections 63.1026(e)(1)-(2) in Subpart UU. The Working 

Group, therefore, suggests the following corrections to Section 63.11915 to clarify and 

resolve this issue (new text is underlined; deletions are in strikethrough):

 4 77 Fed. Reg. 22,880.
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§ 63.11915 What are my compliance requirements for 

equipment leaks?

For equipment in HAP service (as defined in § 63.12005), you must 

comply with the requirements in paragraphs (a) and (b) of this 

section. For pressure relief devices in HAP service, you must 

comply with the requirements in paragraphs (a) through and (c) of 

this section.5

(a) Requirement for certain equipment in subpart UU of this part. 

You must comply with §§ 63.1020 through 63.1025, 63.1027, 

63.1029 through 63.1032, and 63.1034 through 63.1039 of subpart 

UU of this part.

(b) Alternative Requirements for pumps, compressors, and agitators. 

You must meet the requirements of paragraphs (b)(1) and (2) of this 

section. For each type of equipment specified in paragraphs (b)(1) 

and (2) of this section, you must also meet the requirements of

paragraph (a) of this section.

(1) Rotating pumps. HAP emissions from seals on all rotating

pumps, compressors, and agitators in HAP service are to may be 

minimized by either installing sealless pumps, pumps with double 

mechanical seals or equivalent equipment, or by complying with the

requirements of 40 CFR part 63, subpart UU for rotating pumps. If 

double mechanical seals are used, emissions from the seals are to 

be minimized by maintaining the pressure between the two seals so 

that any leak that occurs is into the pump; by complying with § 

63.11925(a) and (b); or equivalent equipment or procedures 

approved by the Administrator. You must also meet the reporting, 

recordkeeping, and inspection provisions applicable to each piece of 

equipment under subpart UU of this part.

(2) Reciprocating pumps, rotating compressors, reciprocating 

compressors and agitators. HAP emissions from seals on all 

reciprocating pumps, rotating compressors, reciprocating 

compressors and agitators in HAP service are to be minimized by 

either installing double mechanical seals or equivalent equipment, or 

by complying with the requirements of 40 CFR part 63, subpart UU 

for reciprocating pumps, rotating compressors, reciprocating 

compressors and/or agitators. If double mechanical seals are used, 

HAP emissions from the seals are to be minimized by maintaining 

the pressure between the two seals so that any leak that occurs is

 5 This language is proposed solely as a technical correction to the PVC MACT’s cross-references to 

Subpart UU, and neither waives nor rescinds substantive objections to the pressure relief device 

provisions the Working Group raised in its June 18, 2012 Petition for Reconsideration.
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into the pump; by complying with § 63.11925(a) and (b); or 

equivalent equipment or procedures approved by the Administrator.

The revisions proposed above also would address the issues raised in the next 

two sections, which are dealt with separately in the event EPA follows a different option.

B. Open-Ended Lines (77 Fed. Reg. 22,911–12; codified at 40 C.F.R. § 

63.11915) 

As with pumps and similar equipment, as described in the previous question, 

there is some confusion concerning the requirements applicable to open-ended lines 

(“OELs”). According to the Agency, OELs are subject to the equipment leak provisions 

of the rule; however, the express language of the final rule excludes OELs. 

Accordingly, EPA should make minor modifications to the regulatory text to affirmatively 

state that OELs are covered. 

Specifically, with regard to OELs, EPA indicated as follows:

Lastly, preamble Section IV.A. states that a PVCPU includes 

“equipment,” which in turn includes items such as open-ended 

valves or lines, sampling connection systems, and pressure relief 

devices needed for safety purposes. Therefore, equipment leak 

provisions do apply to these types of equipment.6

Indeed, the regulatory definition of “equipment” under the PVC MACT expressly 

lists OELs:

Equipment means each pump, compressor, agitator, pressure relief 

device, sampling connection system, open-ended valve or line, 

valve, connector and instrumentation system in HAP service; and 

any control devices or systems used to comply with this subpart.7 

(Emphasis added.)

Confusion arises in how the Agency has allocated the applicable equipment leak 

requirements at Section 63.11915. That section provides that:

For equipment in HAP service (as defined in § 63.12005), you must 

comply with the requirements in paragraphs (a) through (c) of this 

section.8

By their plain language, however, paragraphs (a) through (c) only apply to 

specific pieces of equipment and are silent regarding OELs. Paragraphs (b) and (c) are 

inapplicable here because they apply solely to pumps, compressors, agitators, and 

 6 Summary of Public Comments and Responses (Document No. EPA-HQ-OAR-2002-0037-0185), at 15-

85 to 15-86.

7 40 C.F.R. § 63.12005.

8 40 C.F.R. § 63.11915.
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pressure relief devices. Paragraph (a), which is intended to address “certain 

equipment,” arguably would apply, as it references the Subpart UU standards for 

equipment leaks. However, the final regulatory text appears to specifically exclude the 

Subpart UU standards for OELs at Section 63.1033, and provides no reference to other 

standards that would be appropriate for this type of equipment:

Requirement for certain equipment in subpart UU of this part. You 

must comply with §§ 63.1020 through 63.1025, 63.1027, 63.1029 

through 63.1032, and 63.1034 through 63.1039 of subpart UU of this 

part.9

The PVC MACT Working Group assumes that this omission was an oversight, as 

Section 63.1033 had been included in the proposed rule, as follows:

Requirement for certain equipment in subpart UU of this part. You 

must comply with §§ 63.1020 through 63.1025, § 63.1027, and §§ 

63.1029 through 63.1039 of subpart UU of this part.10 (Emphasis 

added.)

Should the Agency not revise Section 63.11915 as suggested in the preceding 

discussion, the Working Group recommends that EPA make the following minor 

correction to Section 63.11915(a) (new text is underlined; deletions are in 

strikethrough), to confirm the applicability of the equipment leak provisions to OELs: 

Requirement for certain equipment in subpart UU of this part. You 

must comply with §§ 63.1020 through 63.1025, 63.1027, and

63.1029 through 63.1032, and 63.1034 through 63.1039 of subpart 

UU of this part.

C. Reciprocating Compressors and Agitators (77 Fed. Reg. 22,911–12; 

codified at 40 C.F.R. § 63.11915) 

The LDAR provisions are also causing some confusion, because it appears to 

refer to “reciprocating agitators,” a piece of equipment that is not present at PVC 

facilities:

Reciprocating pumps, rotating compressors, reciprocating 

compressors and agitators. HAP emissions from seals on all 

reciprocating pumps, rotating compressors, reciprocating 

compressors and agitators in HAP service are to be minimized by 

either installing double mechanical seals or equivalent equipment, or 

by complying with the requirements of 40 CFR part 63, subpart UU 

for reciprocating pumps, rotating compressors, reciprocating 

 9 40 C.F.R. § 63.11915(a).

10 76 Fed. Reg. 29,528, 29,566. 
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compressors and/or agitators. If double mechanical....11 

(Emphasis added.)

Should EPA not revise Section 63.11915 as suggested in the preceding question 

concerning pumps, the Working Group suggests that a “,” be inserted in this 

subparagraph following each instance of “reciprocating compressors” to make clear that 

this provision applies to agitators or reciprocating compressors, as follows (new text is 

underlined):

Reciprocating pumps, rotating compressors, reciprocating 

compressors, and agitators. HAP emissions from seals on all 

reciprocating pumps, rotating compressors, reciprocating 

compressors, and agitators in HAP service are to be minimized by 

either installing double mechanical seals or equivalent equipment, or 

by complying with the requirements of 40 CFR part 63, subpart UU 

for reciprocating pumps, rotating compressors, reciprocating 

compressors, and/or agitators. If double mechanical....

D. Compliance Report (77 Fed. Reg. 22,932; codified at 40 C.F.R. §

63.11985(b)(1))

The Working Group requests clarification from the Agency on the compliance 

report requirements applicable to equipment leaks from pressure vessels. The PVC 

MACT currently states: 

You must include a copy of the inspection record specified in § 

63.11990(b)(2) for each storage vessel when a defect, failure, or 

leak is detected. You must also include a copy of the applicable 

information specified in § 63.1039(b)(5) through (8) of subpart UU of 

this part for each pressure vessel.

12 (Emphasis added.)

The referenced provisions in Sections 63.1039(b)(5)-(8) apply to valves, pumps, 

and alternative means of emissions limitations for batch processes, as well as require

additional reporting for new sources and when changes are made to the method of 

compliance, none of which appear relevant to pressure vessels. Accordingly, the 

Working Group requests that EPA delete this reference, as illustrated below (deletion is 

in strikethrough):

You must include a copy of the inspection record specified in § 

63.11990(b)(2) for each storage vessel when a defect, failure, or 

leak is detected. You must also include a copy of the applicable 

information specified in § 63.1039(b)(5) through (8) of subpart UU of 

this part for each pressure vessel.

 11 40 C.F.R. § 63.11915(b)(2).

12 40 C.F.R. § 63.11985(b)(1).
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E. Inspection of Repaired Equipment Leaks (77 Fed. Reg. 22,940; codified at 

40 C.F.R. § 63.12005)

The Working Group requests clarification from the Agency concerning the 

definitions of the terms “first attempt at repair” and “repaired,” particularly as they relate 

to the inspection of equipment leaks and other requirements. For example, “repaired” is 

defined as:

Repaired, for the purposes of this subpart, means equipment that is 

adjusted or otherwise altered to eliminate a leak as defined in the 

applicable sections of this subpart; and unless otherwise specified in 

applicable provisions of this subpart, is inspected as specified in §

63.11930(f) to verify that emissions from the equipment are below 

the applicable leak definition.13 (Emphasis added.)

The Working Group submits that the reference to Section 63.11930(f) is 

confusing for a general definition of “repaired,” as that provision deals with leak repairs 

for closed vent systems. Nor does the “unless otherwise specified” clause fully clarify 

the issue, as inspection and repair provisions for various types of equipment actually 

are specified in other subparts. For example, as equipment leaks are subject to 

Subpart UU, such leaks would be repaired in accordance with the Subpart UU 

definition, which references Sections 63.1023(b) and (c), rather than Section 

63.11930(f). Similarly, as floating roof storage vessels are subject to the operating, 

inspection, repair, and maintenance requirements of 40 C.F.R. Part 63, Subpart WW,14

inspection pursuant to Section 63.11930(f) also does not appear to apply. 

Accordingly, the Working Group requests that the Agency confirm that the 

inspection process in Section 63.11930(f) applies to the repair of equipment for which 

inspection and repair requirements under another subpart have not been expressly 

specified.

III. Deviations (77 Fed. Reg. 22,909, 22,911–12; codified at 40 C.F.R. §§

63.11890, 63.11915) 

The Working Group requests that the Agency confirm that leaks and pressure 

relief valve discharges from equipment not in HAP service are not violations under the 

PVC MACT, because such equipment is not within the scope of the requirements in 

Section 63.11915. 

IV. Heat Exchange Systems

A. MACT Floor (77 Fed. Reg. 22,912–14; codified at 40 C.F.R. § 63.11920) 

The Working Group requests that EPA provide clarification on the method used 

to calculate the MACT floor for the leak threshold limits and work practice standards for 

 13 40 C.F.R. § 63.12005.

14 40 C.F.R. § 63.11910(b).
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heat exchange systems. According to Table 3-62 in the MACT floor analysis 

document,

15 the same OxyVinyls Pasadena cooling tower was counted twice with a leak 

threshold limit of 50 ppbw for both speciated VOCs and VOCs. The Working Group

believes that this double counting of the same cooling tower’s leak threshold limits and

the mixing of threshold limits for both VOCs and speciated VOCs in Table 3-62 is in

error, and requests that EPA clarify how these values were calculated.

B. Test Method (77 Fed. Reg. 22,912; codified at 40 C.F.R. § 63.11920)

In Section 63.11920(a)(3)(ii), the Agency specifies the use of Method 624 for 

strippable VOCs in cooling water, rather than the equivalent Method SW-846-8260B 

used elsewhere in the rule for strippable VOCs. Although these methods are 

equivalent, laboratories must be certified in the particular method used. Furthermore, 

Method 8260B is used in other parts of the PVC MACT and allowing its use here would 

increase consistency within the final rule.16 Accordingly, the Working Group 

recommends that the Agency make the following minor corrections to Section 

63.11920(a)(3)(ii) (new text is underlined):

Determine the total strippable volatile organic compounds 

concentration (in parts per billion by weight) in the cooling water 

using Method 624 at 40 CFR part 136, appendix A, or Method SW846-8260B. The target list of compounds shall be generated based 

on a pre-survey sample and analysis by gas chromatography/mass 

spectrometry and process knowledge to include all compounds that 

can potentially leak into the cooling water. If Method 624 of part 

136, appendix A, or Method SW-846-8260B is not applicable for all 

compounds that can potentially leak into the cooling water for a 

given heat exchange system, you cannot use this monitoring 

method for that heat exchange system.

V. Process Vents

A. Batch and Continuous Process Vent Definitions (77 Fed. Reg. 22,914, 

22,937; codified at 40 C.F.R. §§ 63.11925, 63.12005) 

The definitions for both “batch process vent” and “continuous process vent” 

contain the phrasing “a vent...from a PVCPU through which a HAP-containing gas 

stream has the potential to be released to the atmosphere....” (Emphasis added.) The 

plain language of Section 63.11925(b) clearly states that the closed vent system 

requirements only apply to batch and continuous process vents “in HAP service.” 

Accordingly, the Working Group requests that EPA confirm that only process vents in 

HAP service, rather than those that contain any HAP, are subject to these requirements. 

 15 Document No. EPA-HQ-OAR-2002-0037-0193.

16 In addition to consistency, another advantage of Method 8260B is that its specified analyte list is longer 

(i.e., more HAPs are verified as appropriate analytes for the method) and more options are available to 

optimize the method for specific HAPs (e.g., heated purge). 
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The Working Group also requests that the Agency confirm that inorganic HAPs 

are not considered in determining whether a vent stream is in HAP service, as stated in 

the “in HAP service” definition:

In HAP service means that a process component either contains or 

contacts a liquid that is at least 5-percent HAP by weight or a gas 

that is at least 5 percent by volume HAP as determined according to 

the provisions of § 63.180(d). For the purposes of this definition, 

the term ‘‘organic HAP’’ as used in § 63.180(d) [determined 

using Method 18 of part 60, appendix A] means HAP. The 

provisions of § 63.180(d) also specify how to determine that a 

process component is not in HAP service.17 (Emphasis added.)

B. Process Vent Definition (77 Fed. Reg. 22,937, 22,939, 22940; codified at 

40 C.F.R. § 63.12005) 

The Working Group submits that it would be helpful to the PVC industry if the 

PVC MACT provided clear indication of what equipment and process components are 

not considered process vents (batch, continuous, or miscellaneous), as is done in the 

VCM NESHAP and the HON (see, for example, 40 C.F.R. § 63.107, Identification of 

process vents subject to this subpart). Although the scope of the process vent and 

closed vent system requirements can be determined from reading the rule as a whole, 

confusion may arise as to whether some equipment and process components (e.g.,

leaks, opened equipment, storage tanks, and vents from equipment not in HAP service) 

could be regulated under more than one primary section of the rule. The Working 

Group requests that the Agency consider revising the definition of process vent (or, 

alternatively, the definitions of batch process vent, continuous process vent, and 

miscellaneous vent) to make this distinction.

C. Sweep Gases (77 Fed. Reg. 22,914, 22,927–28; codified at 40 C.F.R. §§

63.11925, 63.11955)

The Working Group requests confirmation that the use of sweep gases is 

permitted under the rule as part of the procedure used to clear process components and 

equipment under the equipment opening provisions. Under current industry practice, 

certain amounts of sweep gases are sent through closed piping to the recovery system,

while others, such as steam evacuation, are sent to the control device. The Agency

acknowledges the use of sweeping in the preamble to the final rule:

...we are requiring work practices that require venting the emissions 

from process components and equipment through a closed vent 

system to a control device prior to opening to minimize emissions. 

This is typically achieved by sweeping the component or equipment 

 17 40 C.F.R. § 63.12005.
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several times with nitrogen to reduce the concentration of HAP in 

the vapor space of the component or equipment.18

Sweep gases are not mentioned, however, in the equipment opening provisions 

in Section 63.11955. Although the Agency states in Section 63.11925(a) that “emission 

limits in Table 1 or 2 to this subpart must not be met through dilution,” the Working 

Group does not believe that the Agency intended to prohibit sweeping, even if it has 

some dilutive effect. The Working Group recommends the following minor correction to 

Section 63.11925(a) to resolve this uncertainty (new text is underlined): 

Emission limits. Each process vent must meet the emission limits in 

Table 1 or 2 to this subpart prior to the vent stream being exposed to 

the atmosphere. The emission limits in Table 1 or 2 to this subpart 

apply at all times. The emission limits in Table 1 or 2 to this subpart 

must not be met through dilution. Gas or steam sweeping prior to 

opening equipment or process components in accordance with § 

63.11955 is not considered dilution.

The Working Group would also like to confirm that other methods, such as 

steam, may be used to sweep equipment prior to opening.

D. Miscellaneous Vents and Samples (77 Fed. Reg. 22,914–16, 22,939; 

codified at 40 C.F.R. §§ 63.11925, 63.12005) 

The Working Group requests clarification of the miscellaneous vent requirements 

applicable to gaseous emissions from samples. The plain language of the 

miscellaneous vent definition indicates that only gaseous emissions from samples are 

intended to be covered: 

Miscellaneous vent means gaseous emissions from samples, 

loading and unloading lines... .19 (Emphasis added.)

This creates significant questions within the industry as to how such control can 

be achieved. Under the VCM NESHAP, PVC facilities were required to address 

emissions from samples as follows: 

Samples. Unused portions of samples containing at least 10 

percent by weight vinyl chloride are to be returned to the process or 

destroyed in a control device from which concentration of vinyl 

chloride in the exhaust gas does not exceed 10 ppm (average for 3-

hour period) or equivalent as provided in § 61.66. Sampling 

techniques are to be such that sample containers in vinyl chloride 

service are purged into a closed process system. Compliance with 

 18 77 Fed. Reg. 22,885.

19 40 C.F.R. § 63.12005.
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the provisions of 40 CFR part 61 subpart V demonstrates 

compliance with the provisions of this paragraph.20 

Arguably, the Agency intended to transfer this approach to the PVC MACT when 

in its response to comments document it noted:

While we agree that samples are not process vents, the part 61 rule 

required that samples be returned to the process and emissions 

controlled to meet 10 ppmv of vinyl chloride. The final rule, [sic] we 

include samples as miscellaneous vents and require that emissions 

from miscellaneous vents be controlled to meet the applicable 

process vent emission limit.21

Limiting gaseous emissions from samples makes sense when they are stored in 

hermetically sealed containers from which no emissions escape. It is not clear, 

however, whether EPA intended to include sample collection and analysis as part of the 

miscellaneous vent definition. Because the PVC MACT regulations require that a 

“miscellaneous vent that is in HAP service must be routed through a closed vent system 

to a control device...”22 there are practical and logistical barriers to complying with these 

requirements for certain samples. For example, certain facilities have slip stream 

sample analyzers that route back to the process. 

In addition, vent hoods at plant laboratories, which do not fit under the definition 

of the PVCPU, are primarily used for personnel protection when samples are analyzed, 

and for the most part have no practical means of collecting emissions. Lastly, Subpart 

UU, Section 63.1032, already regulates the sampling of process fluids, and allows 

purging samples into a container, provided the container is kept covered or closed when 

not being filled or emptied. The Working Group requests that the Agency clarify the 

scope of the miscellaneous vent requirements as they apply to samples. 

VI. CEMS (77 Fed. Reg. 22,914–16; codified at 40 C.F.R. § 63.11925)

The Working Group requests that the Agency clarify the specific continuous 

emission monitoring system (“CEMS”) that can be used to replace each continuous 

parameter monitoring system (“CPMS”). The final rule allows CEMS to be used “in lieu 

of establishing operating limits in §63.11880(b) and using CPMS to comply with the 

operating limits, as specified in §63.11940(a) through (h).”23 The confusion arises, 

however, because the rule does not make clear in Sections 63.11940(a) through (h) and 

Table 7 how CEMS can be substituted for CPMS in practice if a combination of CEMS 

and CPMS is used to meet the emission limits in the rule. The Working Group requests 

 20 40 C.F.R. § 61.65(b)(7).

21 Summary of Public Comments and Responses (Document No. EPA-HQ-OAR-2002-0037-0185), at 10-

57.

22 40 C.F.R. § 63.11925(b).

23 40 C.F.R. §§ 63.11925(c)(1), (2) and (3).
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that the Agency clarify which CEMS can be substituted for which CPMS requirements, 

on a control-technology-by-control-technology basis. The table below, which compares

these requirements for existing major sources, has been prepared by the Working 

Group for the Agency’s reference and further discussion.

The Working Group also seeks clarification concerning the process for gaining 

approval for a vinyl chloride CEMS. Although CEMS are listed in Section 11925(c) for 

several HAPs regulated by the PVC MACT, paragraph (c) does not include a vinyl 

chloride CEMS in addition to the CEMS already allowed (i.e., HCl, THC, and TEQ). By 

way of background, several PVC facilities currently use a VCM analyzer (i.e., a CEMS) 

for control devices, and would prefer to continue using this established method of 

monitoring process vent emissions. The Working Group requests that the Agency 

provide guidance for these PVC facilities on using existing vinyl chloride CEMS to 

comply with the PVC MACT. The Working Group also requests that the Agency clarify 

the compliance period (i.e., an averaging basis of 1 hour or 3 hours) and other 

requirements that would apply once CEMS is implemented. If it is not possible for the 

Agency to develop industry-wide standards at this time, the Working Group requests 

that the Agency indicate whether vinyl chloride CEMS could be approved on a facilityby-facility basis through a Relative Accuracy Test Audit (“RATA”).

VII. Drums, Pails, and Totes (77 Fed. Reg. 22,914–16, 22,939; codified at 40 

C.F.R. §§ 63.11925, 63.12005)

The Working Group seeks confirmation of statements by EPA staff to Working 

Group members that totes and similar containers of raw materials, ingredients, 

treatment chemicals, etc. – which would meet the definition of “in HAP service,” but for 

CPMS for Various Equipment That Could be Eliminated With CEMS

CEMS to 

Measure

Emission Limitsa Thermal 

Oxidizer Absorber/Scrubber VGA Condenser

PVCOnlyPVCCombined

Vinyl Chloride 6.0 ppmv 1.1 ppmv Temp

air flow, bed temp, 

regeneration time, 

VOC out

Exit Temp

Hydrogen 

Chloride 78 ppmv 380 ppmv pH, liquid flow, 

Delta P, air flow

Total 

Hydrocarbons 

(“THC”) or 

Total Organic 

HAPb

9.7 ppmv 

as 

propane

4.2 ppmv 

as 

propane Temp, 

O2c

air flow, bed temp, 

regeneration time, 

VOC out

Exit Temp

56 ppmv 9.8 ppmv

Dioxins/Furans 

(“TEQ”)

0.038 

ng/dscm

0.051 

ng/dscm

Temp, 

O2c

liquid flow, inlet 

temp, TO inlet 

conc.? / air flow? a ppmv = parts per million by volume dry at three percent oxygen (“O2”). ng/dscm = nanograms per dry standard cubic meter at 

three percent O2, limits for existing major sources. b Total Organic HAP is alternative limit for THC. c Oxygen not regulated by CPMS in rule.
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the fact that they are not “process components” – are not subject to the emission 

limitations at Table 1 and Table 2 of the PVC MACT. This stated position agrees with 

the plain language of the PVC MACT as it relates to drums, pails, totes, and other 

containers used to hold these materials, as discussed below. 

As an initial matter, only process components are considered to be “in HAP 

service” under the PVC MACT final rule:

In HAP service means that a process component either contains 

or contacts a liquid that is at least 5-percent HAP by weight or a gas 

that is at least 5 percent by volume HAP as determined according to 

the provisions of § 63.180(d). For the purposes of this definition, the 

term ‘‘organic HAP’’ as used in § 63.180(d) means HAP. The 

provisions of § 63.180(d) also specify how to determine that a 

process component is not in HAP service.24 (Emphasis added.)

The term “process component”, as defined in the PVC MACT, is intended to include 

parts and equipment permanently connected to perform a particular function within the 

PVCPU, and does not include unconnected vessels:

Process component means any unit operation or group of units 

operations or any part of a process or group of parts of a process 

that are assembled to perform a specific function (e.g., 

polymerization reactor, dryers, etc.). Process components include 

equipment, as defined in this section.25 (Emphasis added.)

By comparison, drums, pails, totes, and other small vessels are defined as

“containers,” which would not fall within the definition of process component as quoted 

above:

Container means a portable unit in which a material can be stored, 

transported, treated, disposed of or otherwise handled. Examples of 

containers include, but are not limited to, drums, pails, and portable 

cargo containers known as “portable tanks” or “totes.” Container 

does not include transport vehicles or barges.26 

“Equipment” is included in the definition of process component, but containers clearly 

are not equipment under the final rule:

Equipment means each pump, compressor, agitator, pressure relief 

device, sampling connection system, open-ended valve or line, 

valve, connector and instrumentation system in HAP service; and 

any control devices or systems used to comply with this subpart.27

 24 40 C.F.R. § 63.12005.

25 40 C.F.R. § 63.12005.

26 40 C.F.R. § 63.12005.

27 40 C.F.R. § 63.12005.
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Based on the plain language of the rule, containers are not “in HAP service” and,

therefore, are not subject to the Table 1 and Table 2 emission limits. This comports 

with how containers are currently handled by PVC facilities, and is the only practical 

approach given that emissions from containers can only be controlled through work 

practice standards. Work practice standards are appropriate where a HAP “cannot be 

emitted through a conveyance designed and constructed to emit or capture such 

pollutant, or that any requirement for, or use of, such a conveyance would be 

inconsistent with any Federal, State or local law.”28 Existing practice in the PVC 

industry is to keep containers closed unless adding or removing material. The Working 

Group requests that the Agency confirm that containers are not subject to the Table 1 

and Table 2 emission limits under the final rule. 

VIII. Vacuum Systems (77 Fed. Reg. 22,916–19; codified at 40 C.F.R. § 63.11930) 

The PVC MACT Working Group is requesting clarification as to the scope of the 

vacuum system provisions codified at 40 C.F.R. § 63.11930(h). It appears from the 

language of the reporting provision that the Agency intends for vacuum systems to 

operate continuously, but all PVC facilities also currently use an intermittent vacuum 

system normally routed to a recovery system for evacuating equipment prior to opening. 

We believe that the intent of the Agency was to require continuous vacuum when the 

closed vent system is not operating under the standard closed vent system 

requirements or has not been opened following the equipment opening procedures, as 

we discuss below. 

Section 63.11930(h) provides that a closed vent system must either operate in 

vacuum service, as defined by the rule, or comply with the closed vent system 

requirements in paragraphs (a) through (g): 

Closed vent systems in vacuum service. If you operate and 

maintain a closed vent system in vacuum service as defined in § 

63.12005, you must comply with the requirements in paragraphs 

(h)(1) through (3) of this section, and you are not required to comply 

with any other provisions of this section. Any incidence where a 

closed vent system designed to be in vacuum service is 

operating and not in vacuum service constitutes a violation of 

this rule, unless the closed vent system is meeting the 

requirements in paragraphs (a) through (g) of this section for 

closed vent systems that are not in vacuum service. Any such 

incidence during a performance test invalidates the performance 

test. (Emphasis added.)

The plain language thus comports with the way PVCPUs are designed: vacuum 

is used intermittently to evacuate equipment and clear the closed vent system, which is 

otherwise routed to a control device. These requirements apply when the closed vent 

system is “operating” and in HAP service. Equipment opening work practice standards

 28 42 U.S.C. § 7412(h)(2)(A).
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to remove the closed vent system from HAP service apply to the closed vent system 

when it is not in operation, as well as to individual piping or components that are taken 

out of service apart from the closed vent system as a whole. We ask that EPA confirm 

this clear reading of the language in the rule.

Where the potential for confusion arises, however, is with paragraph (h)(3), which 

states:

In vacuum service alarm records and reports. For any incidences 

where a closed vent system designed to be in vacuum service 

is not in vacuum service, you must submit to the Administrator 

as part of your compliance report, the information specified in § 

63.11985(b)(10) [deviation report]. This report is required even if 

you elect to follow the procedures specified in § 63.11895 to 

establish an affirmative defense and submit the reports specified in 

§ 63.11985(b)(11). (Emphasis added.)

The deviation reporting requirement of paragraph (h)(3) does not appear to 

recognize that a closed vent system may: (1) operate as a closed vent system in 

compliance with paragraphs (a) through (g); (2) operate in vacuum service in 

compliance with paragraph (h); or (3) be out of operation following implementation of 

the equipment opening procedures. 

As written, paragraph (h)(3) not only conflicts with paragraph 63.11930(h) 

reproduced above, but would require deviation reporting in circumstances where no 

actual deviation or discharge occurred, because the closed vent system is still in 

compliance with either paragraphs (a) through (g) or the equipment opening work 

practice standards. Accordingly, the Working Group suggests the following minor 

corrections to the language of Section 63.11930(h)(3) (new text is underlined):

In vacuum service alarm records and reports. For any incidences 

where a closed vent system in HAP service designed to be in 

vacuum service is operating and both not in vacuum service and not 

meeting the requirements in paragraphs (a) through (g) of this 

section, you must submit to the Administrator as part of your 

compliance report, the information specified in § 63.11985(b)(10). 

This report is required even if you elect to follow the procedures 

specified in § 63.11895 to establish an affirmative defense and 

submit the reports specified in § 63.11985(b)(11). 

IX. CPMS (77 Fed. Reg. 22,920–22, 22,945–46; codified at 40 C.F.R. § 63.11940, 

Table 5) 

As currently worded, Table 5 appears to impose broad CPMS requirements even 

in circumstances when the control technology at issue is not used. Table 5 states this 

requirement as follows:
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For these control devices, you must monitor these operating 

parameters . . .

For example, not all thermal oxidizers use catalyst beds, yet under the Thermal 

Oxidizer subheading, affected sources are required to monitor the temperature 

differential across the catalyst bed. By comparison, Section 63.11940 makes clear that 

the parametric monitoring required depends on the specific equipment in use, rather 

than applying broadly across all configurations that use a particular control device. 

Similar inconsistencies arise from the Table 5 parameters for absorbers and acid gas 

scrubbers, on the one hand, and the plain language of Section 63.11940(c) and Table 

7, on the other. The Working Group requests that the Agency confirm that Section 

63.11940, rather than Table 5, sets out the parameters that “must” be monitored.

X. Recovery Devices 

A. CPMS (77 Fed. Reg. 22,914, 22,920–22, 22,940; codified at 40 C.F.R. §§ 

63.11925, 63.11940, 63.12005) 

The Working Group requests clarification of the recovery device definition. As 

currently written, it is overly broad, conflicts with the control device definition in certain 

instances, and imposes CPMS requirements on equipment that are outside the 

intended scope of the control device definition. Of relevance here, the control device 

definition makes clear that recovery devices are control devices, but only if they are 

used to comply with the MACT, i.e., to limit emissions: 

Control device means, with the exceptions noted in this definition, a 

combustion device, recovery device, recapture device or any 

combination of these devices used to comply with this subpart. 

Process condensers are not control devices.29 (Emphasis added.)

In contrast, the “recovery device” definition categorically makes all recovery 

devices control devices: 

Recovery device means an individual process component capable 

of and normally used for the purpose of recovering chemicals for 

fuel value (i.e., net positive heating value), use, reuse, or for sale for 

fuel value, use, or reuse. Examples of process components that 

may be recovery devices include absorbers, adsorbers, condensers, 

oil-water separators or organic-water separators, or organic removal 

devices such as decanters, strippers (e.g., wastewater steam and 

vacuum strippers), or thin-film evaporation units. For purposes of 

this subpart, recovery devices are control devices. 

This raises the question of why a recovery device definition is even needed. 

More importantly, the regulations treat as “control devices” recovery devices that were 

 29 40 C.F.R. § 63.12005.
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not used to control emissions when data was collected to set the emission limits or will 

not be used to demonstrate compliance with those limits. 

Some recovery devices are used to recover raw material for reuse prior to routing 

the vent stream to a thermal oxidizer or other “end-of-pipe” control device. Accordingly, 

these recovery devices would not be used to demonstrate initial compliance or to 

achieve ongoing compliance, such that they are not “used to comply with this subpart.” 

An example of such a recovery device is a membrane separator vented to the recovery 

system prior to the thermal oxidizer. PVCPUs equipped with a membrane separator do 

not need to use the membrane separator to comply with the process vent emission 

limits. Thus, these recovery devices arguably do not fall within the definition of “control 

device” and should not be subject to the CPMS requirement of Section 63.11925(c). 

Yet the recovery device definition makes this unclear. Furthermore, some recovery 

devices, such as membrane separators, do not have operating parameters that could 

be monitored by CPMS. For these reasons, we would recommend the following minor 

revision to the “recovery device” definition (new text is underlined):

Recovery device means an individual process component capable 

of and normally used for the purpose of recovering chemicals for 

fuel value (i.e., net positive heating value), use, reuse, or for sale for 

fuel value, use, or reuse. Examples of process components that 

may be recovery devices include absorbers, adsorbers, condensers, 

oil-water separators or organic-water separators, or organic removal 

devices such as decanters, strippers (e.g., wastewater steam and 

vacuum strippers), or thin-film evaporation units. For purposes of 

this subpart, recovery devices are control devices when used to 

comply with this subpart. 

B. Process Condenser (77 Fed. Reg. 22,939; codified at 40 C.F.R. §

63.12005) 

The Working Group also requests clarification of the process condenser 

definition. The final rule defines “process condenser” as equipment used in a batch 

process:

Process condenser means a condenser whose primary purpose is 

to recover material as an integral part of a batch process. All 

condensers recovering condensate from a batch process at or 

above the boiling point or all condensers in line prior to a vacuum 

source are considered process condensers. Typically, a primary 

condenser or condensers in series are considered to be integral to 

the batch regulated process if they are capable of and normally used 

for the purpose of recovering chemicals for fuel value (i.e., net 

positive heating value), use, reuse or for sale for fuel value, use or 

reuse....30

 30 40 C.F.R. § 63.12005.
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Although PVC production is primarily a batch process, the final rule includes both 

batch and continuous operations within its scope. The Working Group does not believe 

that the Agency’s intent was to make batch process condensers a special case. 

Accordingly, the Working Group requests that EPA clarify that both continuous and 

batch process condensers are process condensers under the final rule in the interest of 

consistency. The Working Group suggests the following minor correction to the 

definition of process condenser; in relevant part (new text is underlined):

Process condenser means a condenser whose primary purpose is 

to recover material as an integral part of a batch or continuous

process. All condensers recovering condensate from a batch or 

continuous process at or above the boiling point or all condensers in 

line prior to a vacuum source are considered process condensers. 

Typically, a primary condenser or condensers in series are 

considered to be integral to the batch or continuous regulated

process if they are capable of and normally used for the purpose of 

recovering chemicals for fuel value (i.e., net positive heating value), 

use, reuse or for sale for fuel value, use or reuse....

XI. Gasholders (77 Fed. Reg. 22,928; codified at 40 C.F.R. § 63.11955) 

The Working Group requests that the Agency clarify the requirements applicable 

to gasholders. The language of Section 63.11955(d)(1) provides as follows: 

Each gasholder must be vented to a closed vent system and control 

device meeting the requirements of §§ 63.11925 through 

63.11950.31

Most gasholders currently return recovered gas back to an enclosed process for 

reuse in the manufacturing process. The Working Group requests that the Agency 

confirm that gasholders are permitted to return the recovered gas back to the process, 

provided the process is enclosed and ultimately vents to a closed vent system.

XII. Ambient Monitoring

A. Area Monitoring Plan (77 Fed. Reg. 22,928; codified at 40 C.F.R. §

63.11956) 

By the plain language of the area monitoring provisions, an affected source is not 

required to resubmit an area monitoring plan if it has already been approved:

You must operate a reliable and accurate vinyl chloride monitoring 

system for detection of major leaks and identification of the general 

area of the affected source where a leak is located...You must 

operate the vinyl chloride monitoring system according to a program 

that you develop for your affected source. You must submit a 

 31 40 C.F.R. § 63.11955(d)(1).
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description of the program to the Administrator within 45 days of 

your compliance date, unless a waiver of compliance is granted by 

the Administrator, or the program has been approved and the 

Administrator does not request a review of the program. Approval of 

a program will be granted by the Administrator provided the 

Administrator finds....

32 (Emphasis added.)

This language mirrors the requirements of the VCM NESHAP for area 

monitoring:

A reliable and accurate vinyl chloride monitoring system shall be 

operated for detection of major leaks and identification of the 

general area of the plant where a leak is located...The vinyl chloride 

monitoring system shall be operated according to a program 

developed by the plant owner or operator. The owner or operator 

shall submit a description of the program to the Administrator within 

45 days of the effective date of these regulations, unless a waiver of 

compliance is granted under § 61.11, or the program has been 

approved and the Administrator does not request a review of the 

program. Approval of a program will be granted by the Administrator 

provided he finds....

33 (Emphasis added.)

Thus, it does not appear that the Agency intended to change the area monitoring 

plan approval requirements from those currently applicable to PVC facilities under the 

VCM NESHAP. Nevertheless, the phrase “has been approved” raises the question of 

whether formal or explicit approval must be received, and from what entity, the State or 

EPA. Currently, PVC facilities operate under an area monitoring plan that was 

submitted to EPA or the State (where EPA has delegated its Clean Air Act Section 112 

authority to the State under Section 112(l) of the Act). In some instances, area 

monitoring plans were never formally or explicitly approved by either EPA or the States, 

which in our view, is in keeping with the regulatory language.

The Working Group is aware of at least one instance, however, where an 

enforcement action was initiated against a facility for failing to obtain prior approval of a 

plan change. The violation was dropped once the facility demonstrated to EPA that it 

had submitted the plan change to the State, but the language and scope of the 

provision continue to cause significant confusion within the industry. Consequently, the 

Working Group recommends the following minor correction to Section 63.11956 to 

make clear that submission is required only if the area monitoring plan was not 

previously submitted to EPA or the State, as appropriate (new text is underlined; 

deletions are in strikethrough): 

You must operate a reliable and accurate vinyl chloride monitoring 

system for detection of major leaks and identification of the general 

 32 40 C.F.R. § 63.11956.

33 40 C.F.R. § 63.65(b)(8)(i).
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area of the affected source where a leak is located...You must 

submit a description of the program to the Administrator within 45 

days of your compliance date, unless a waiver of compliance is 

granted by the Administrator, or the program has been previously 

submitted to, and not rejected by, an authorized state, approved and 

the Administrator does not request a review of the program.

Approval of a program will be granted by the Administrator provided 

the Administrator finds....

B. Test Method for Area Monitoring (77 Fed. Reg. 22,928; codified at 40 

C.F.R. § 63.11956) 

The PVC MACT provides for calibration of the vinyl chloride area monitoring 

system in accordance with Method 106 and calls for using a calibration curve in the 

area monitoring provisions, as follows: 

...If a gas chromatograph is used as the vinyl chloride monitoring 

system, these gas mixtures may be directly used to prepare a 

chromatograph calibration curve as described in Sections 8.1 and 

9.2 of Method 106.34

The Working Group believes that single point calibration is adequate for the area 

monitoring system, and is the current industry standard approved by state monitoring 

plans. Gas chromatography machines used in the area monitoring system are typically 

benchmarked everyday with the same vinyl chloride standard used to calibrate the 

analyzer. The Working Group requests that EPA confirm that single point calibration is 

acceptable under Method 106 and recommends that the above quoted text be removed 

from the rule. 

XIII. Stripped Resin

A. Grab Samples (77 Fed. Reg. 22,928–29; codified at 40 C.F.R. §

63.11960)

The Working Group requests that the Agency clarify the analysis requirements 

for non-VC TOHAP grab monthly samples that must be collected during the 24-hour 

sampling period. Specifically, the Working Group requests that the Agency confirm that, 

under Sections 63.11960(c)(1)(iii) and (iv), the three grab samples can be composited

prior to analysis by the laboratory, as was done pursuant to the PVC MACT Section 114 

data collection. 

 34 40 C.F.R. § 63.11956(d)(2).
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B. Site-Specific HAP List (77 Fed. Reg. 22,928; codified at 40 C.F.R. §

63.11960, Table 10) 

Under the final rule, the list of site-specific HAPs for stripped resin and 

wastewater must be “continuously updated.”

35 The Working Group believes that the 

Agency’s intent was for the site-specific HAP list to be continuously up-to-date, rather 

than revised with a specific frequency. The Working Group requests that the Agency 

confirm that updating the HAP list after any process change that would impact the list of 

HAPs (e.g., using a new additive) is sufficient to meet this requirement. 

XIV. Wastewater

A. Initial Determination (77 Fed. Reg. 22,930; codified at 40 C.F.R. §

63.11965) 

The Working Group seeks clarification concerning the use of process knowledge 

and engineering judgment to identify which wastewater streams must be treated prior to 

exposure to the atmosphere. Under the current VCM NESHAP, which requires that 

process wastewaters over 10 ppmw vinyl chloride are treated to 10 ppmw, engineering 

judgment is used to select those wastewater streams that must be treated. By the plain 

language of the final PVC MACT, process wastewater streams that are currently treated 

do not need to be retested to ensure that they require treatment; testing is only required 

at the outlet of the treatment process to determine if the current treatment is sufficient:

For treated process wastewater streams, you must collect process 

wastewater samples at the outlet of the treatment process and 

before the process wastewater stream is mixed with any other 

process wastewater stream containing vinyl chloride or total nonvinyl 

chloride organic HAP concentrations less than the applicable limits 

specified in Table 1 or 2 to this subpart, before being exposed to the 

atmosphere, and before being discharged from the affected 

source.36 (Emphasis added.)

The Working Group requests that the Agency confirm that process streams that 

are currently treated do not need to be retested prior to treatment as part of the initial 

determination. 

With regards to currently untreated process wastewater streams, the Working 

Group requests that the Agency clarify that if a currently untreated wastewater stream is 

analyzed for vinyl chloride concentration in accordance with Section 63.11965(b)(2) and 

is found to need treatment, the PVC facility does not need to test that wastewater 

stream for total non-vinyl chloride organic HAP to make the initial determination of 

whether treatment is required.

 35 40 C.F.R. § 63.11960(b).

36 40 C.F.R. § 63.11965(b)(1)(i).
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B. Site-Specific HAP List (77 Fed. Reg. 22,930; codified at 40 C.F.R. §

63.11965, Table 10)

Under the final rule, the list of site-specific HAPs for stripped resin and 

wastewater must be “continuously updated.”37 The Working Group believes that the 

Agency’s intent was for the site-specific HAP list to be continuously up-to-date, rather 

than revised with a specific frequency. The Working Group requests that the Agency 

confirm that updating the HAP list after any process change that would impact the list of 

HAPs (e.g., using a new additive) is sufficient to meet this requirement.

C. Maintenance Wastewater (77 Fed. Reg. 22,930; codified at 40 C.F.R. §

63.11965, Table 4)

Under Section 63.11965(e) of the PVC MACT, affected sources must meet the 

requirements of 40 C.F.R. § 63.105 for maintenance wastewater. Section 63.105(a),

however, references the “organic HAP’s listed in table 9 of subpart G of this part,” which 

is a different list of HAPs than those addressed by the PVC MACT. The Working Group 

does not believe that it was the Agency’s intent to apply a different list of HAPs to the 

maintenance wastewater provision than that used throughout the PVC MACT. 

Consequently, the Working Group recommends the following minor correction to

Section 63.11965(e) to ensure consistency (new text is underlined):

Maintenance wastewater. You must comply with the requirements 

specified in § 63.105 of subpart F of this part. Use the HAP list in 

Table 10, rather than the HAP list referenced by § 63.105(a).

The Working Group also requests that the Agency confirm that the references to 

the startup, shutdown, and malfunction (“SSM”) plan in (d) and (e) of Section 63.105 do 

not apply to the PVC MACT, as SSM plans are not permitted under the PVC MACT. 

The Working Group also requests clarification of the “maintenance wastewater”

definition as it applies to wash water. Specifically, the “maintenance wastewater” 

definition at Section 63.12005 sets out:

...Examples of activities that can generate maintenance 

wastewaters include... water used to wash out process components 

or equipment after the process components or equipment has 

already been opened to the atmosphere and has met the 

requirements of § 63.11955.

The Working Group believes that any water used to wash out process components or 

equipment, after the component or equipment has met the opening requirements in 

Section 63.11955, is classified as maintenance wastewater. The maintenance 

wastewater definition would apply whether or not actual repairs or any other activity 

involving the component or equipment has been performed. This would include wash 

water used on components or equipment prior to inspection and normal washout 

 37 40 C.F.R. § 63.11965(f).
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between batches or products. We request that EPA confirm this interpretation of the 

definition of maintenance wastewater.

D. Wastewater Compliance Reports (77 Fed. Reg. 22,933; codified at 40 

C.F.R. § 63.11985, Table 4) 

In a similar vein, the wastewater information that must be included in compliance 

reports is also difficult to understand due to unclear incorporation of the Part 63 General 

Provisions. As currently written, the PVC MACT leaves the affected source to 

determine what information is “applicable,” as the scope of the General Provisions cited 

does not clearly match that of the PVC MACT: 

If you must comply with § 63.11965, then you must include any 

other applicable information that is required by the reporting 

requirements specified in § 63.146.38

The Agency’s intent regarding this provision is unclear, and the Working Group 

requests that the Agency clarify what other wastewater information must be included in 

compliance reports.

E. Process Wastewater (77 Fed. Reg. 22,940; codified at 40 C.F.R. §

63.12005) 

In the final rule, a new term was added: “process wastewater.” PVC facilities 

reuse large volumes of process water, which should not be considered wastewater. 

The potential confusion arises from the broad definition of process wastewater, which 

includes water from numerous activities, but does not clearly exclude water that is 

reused:

Process wastewater means wastewater that comes into direct 

contact with HAP or results from the production or use of any raw 

material, intermediate product, finished product, by-product, or 

waste product containing HAP, but that has not been discharged 

untreated as wastewater. Examples are product tank drawdown or 

feed tank drawdown; water formed during a chemical reaction or 

used as a reactant; water used to wash impurities from organic 

products or reactants; water used to cool or quench organic vapor 

streams through direct contact; water discarded from a control 

device; and condensed steam from jet ejector systems pulling 

vacuum on vessels containing organics. Gasholder seal water is not 

process wastewater until it is removed from the gasholder.39 

Logically, the definition of process wastewater is limited to water that is in fact 

wastewater (i.e., waste), rather than water that is intended to be reused in the 

 38 40 C.F.R. § 63.11985(b)(8)(ii).

39 40 C.F.R. § 63.12005. 
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manufacturing process. The definition of wastewater, however, only includes a circular 

reference back to process wastewater and maintenance wastewater: 

Wastewater means process wastewater and maintenance 

wastewater. The following are not considered wastewater for the 

purposes of this subpart....40

The Working Group requests that the Agency confirm that water that is reused 

within the PVCPU is not process wastewater and, therefore, is not subject to the 

process wastewater requirements. The Working Group also requests that the Agency 

confirm that process wastewater that meets the process wastewater emission limits 

(either without treatment or after treatment) can be reused in the PVCPU without 

restriction.

F. Dewatering Equipment (77 Fed. Reg. 22,930, 22,940; codified at 40 

C.F.R. §§ 63.11965, 63.12005) 

The Working Group seeks clarification on the requirements applicable to water 

removed during the dewatering and drying of stripped resin. To place this question in 

proper context, it is necessary to consider the resin stripping process, which precedes 

dewatering and drying.

The PVC MACT requires that resin is steam stripped to reduce the air emissions 

of vinyl chloride and other HAP from downstream processes. The material resulting 

from the stripping process is defined by the rule as stripped resin: 

Stripped resin means the material exiting the resin stripper that 

contains polymerized vinyl chloride.41

As EPA recognizes, stripped resin can either exit the stripper in liquid form, also 

referred to as resin slurry, or as a solid:42

... at the outlet of the stripper, the resin is in either a slurry 

(liquid) or dry (solid) form, as opposed to a gaseous stream, as is 

the case for process vents.43 (Emphasis added.)

Stripped resin is stored in feed tanks open to the atmosphere after stripping. 

These feed tanks are not in HAP service because the stripped resin limits have been 

met (taking the HAP concentration well below five percent by weight) and, therefore, the 

storage vessel requirements of Section 63.11910 do not apply. The Working Group 

requests that the Agency confirm this plain reading of the final rule.

 40 40 C.F.R. § 63.12005. 

41 40 C.F.R. § 63.12005.

42 Stripped resin exiting the stripper at all PVC MACT Working Group member facilities is a slurry.

43 77 Fed. Reg. 22,867.
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Stripped resin is then piped from the dryer feed tanks to several types of 

equipment used to remove water (centrifuge, filter press, dryer, etc.), a process called 

dewatering and drying. This process is distinct from resin stripping, as is clear from the 

definition for resin stripper:

Resin stripper means a unit that removes organic compounds from a 

raw polyvinyl chloride and copolymer product. In the production of a 

polymer, stripping is a discrete step that occurs after the 

polymerization reaction and before drying or other finishing 

operations. Examples of types of stripping include steam stripping, 

vacuum stripping, or other methods of devolatilization. For the 

purposes of this subpart, devolatilization that occurs in dryers 

or other finishing operations is not resin stripping. Resin 

stripping may occur in a polymerization reactor or in a batch or 

continuous stripper separate from the polymerization reactor where 

resin stripping occurs.44 (Emphasis added.)

Water removed during the dewatering and drying process is often reused in the 

manufacturing process. As discussed in the previous section, water that is reused is 

not process wastewater and is not subject to the process wastewater limits. Some 

water removed during the dewatering and drying process, however, is discharged to the 

wastewater treatment process as wastewater, and is subject to the wastewater 

requirements of the PVC MACT. The Working Group requests that the Agency confirm 

that this understanding of the requirements applicable to water removed during 

dewatering and drying is correct.

XV. Test Methods (77 Fed. Reg. 22,948; codified at 40 C.F.R. Part 63, Subpart 

HHHHHHH, Table 10) 

The test methods for HAPs identified in Table 10 are not, in some cases, the only 

or even the preferred methods used by commercial laboratories. For example, Table 10 

identifies Method 8015C for ethylene glycol, although Method 8260B is, in practice, the 

method used by some commercial laboratories. Although the Part 63 General 

Provisions procedure for validation and use of an alternative test method (40 C.F.R. § 

63.7(f), which incorporates Method 301) is identified by Table 4 of the final rule as 

applicable to the PVC MACT, the Working Group requests that EPA also allow NELAPcertified45 laboratories to add additional analytes, following demonstration of methodspecific performance criteria, to the PVC MACT listed SW-846 methods, as well as 

allow NELAP-certified laboratories to validate and use alternative test methods for 

testing required by the PVC MACT.

* * *

 44 40 C.F.R. § 63.12005.

45 “NELAP-certified” refers to laboratories accredited by the National Environmental Laboratory 

Accreditation Program administered by the NELAC Institute. See The NELAC Institute’s website 

(http://www.nelac-institute.org/index.php) for more information.
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We appreciate the Agency’s willingness to consider the issues set out above. 

For ease of reference, we include below a table of the topics discussed in this letter.

We look forward to meeting with the appropriate staff members to discuss clarifications 

and guidance after the Agency has taken time to review the many issues raised in this 

letter. As you know, the timing of the Agency’s action on reconsideration is increasingly 

critical as Working Group members must develop plans to implement the PVC MACT, 

and the compliance deadlines associated with the 2012 final rule remain in effect. In 

the interim, please do not hesitate to contact me if you have any questions on these 

issues, or require any additional information.

Sincerely, 

Richard P. Krock

Technical Director

The Vinyl Institute

E-mail: rkrock@vinylinfo.org

Phone: 571-970-3392

Cell: 571-216-4474

cc: Ms. Penny Lassiter, EPA-RTP

Mr. Mark Kataoka, EPA-OCG

Mr. Jean-Cyril Walker, Keller and Heckman LLP

Vinyl Institute PVC MACT Working Group
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PVC MACT Clarifying Question Topics

Section Heading Page

I. Storage Vessels (77 Fed. Reg. 22,910–11, 22,942; codified at 40 C.F.R. § 63.11910, Table 3) 1

II. Equipment Leaks 3

II.A. Reciprocating Pumps, Rotating Pumps, and Similar Equipment (77 Fed. Reg. 22,911–12; 

codified at 40 C.F.R. § 63.11915) 3

II.B. Open-Ended Lines (77 Fed. Reg. 22,911–12; codified at 40 C.F.R. § 63.11915) 5

II.C. Reciprocating Compressors and Agitators (77 Fed. Reg. 22,911–12; codified at 40 C.F.R. § 

63.11915) 6

II.D. Compliance Report (77 Fed. Reg. 22,932; codified at 40 C.F.R. § 63.11985(b)(1)) 7

II.E. Inspection of Repaired Equipment Leaks (77 Fed. Reg. 22,940; codified at 40 C.F.R. § 

63.12005) 8

III. Deviations (77 Fed. Reg. 22,909, 22,911–12; codified at 40 C.F.R. §§ 63.11890, 63.11915) 8

IV. Heat Exchange Systems 8

IV.A. CPMS (77 Fed. Reg. 22,914, 22,920–22, 22,940; codified at 40 C.F.R. §§ 63.11925, 

63.11940, 63.12005) 8

IV.B. Process Condenser (77 Fed. Reg. 22,939; codified at 40 C.F.R. § 63.12005) 9

V. Process Vents 9

V.A. Batch and Continuous Process Vent Definitions (77 Fed. Reg. 22,914, 22,937; codified at 40 

C.F.R. §§ 63.11925, 63.12005) 9

V.B. Process Vent Definition (77 Fed. Reg. 22,937, 22,939, 22940; codified at 40 C.F.R. § 

63.12005) 10

V.C. Sweep Gases (77 Fed. Reg. 22,914, 22,927–28; codified at 40 C.F.R. §§ 63.11925, 

63.11955) 10

V.D. Miscellaneous Vents and Samples (77 Fed. Reg. 22,914–16, 22,939; codified at 40 C.F.R. 

§§ 63.11925, 63.12005) 11

VI. CEMS (77 Fed. Reg. 22,914–16; codified at 40 C.F.R. § 63.11925) 12

VII. Drums, Pails, and Totes (77 Fed. Reg. 22,914–16, 22,939; codified at 40 C.F.R. §§ 63.11925, 

63.12005) 13

VIII. Vacuum Systems (77 Fed. Reg. 22,916–19; codified at 40 C.F.R. § 63.11930) 15

IX. CPMS (77 Fed. Reg. 22,920–22, 22,945–46; codified at 40 C.F.R. § 63.11940, Table 5) 16

X. Recovery Devices 17

X.A. CPMS (77 Fed. Reg. 22,914, 22,920–22, 22,940; codified at 40 C.F.R. §§ 63.11925, 

63.11940, 63.12005) 17

X.B. Process Condenser (77 Fed. Reg. 22,939; codified at 40 C.F.R. § 63.12005) 18

XI. Gasholders (77 Fed. Reg. 22,928; codified at 40 C.F.R. § 63.11955) 19

XII. Ambient Monitoring 19

XII.A. Area Monitoring Plan (77 Fed. Reg. 22,928; codified at 40 C.F.R. § 63.11956) 19

XII.B. Test Method for Area Monitoring (77 Fed. Reg. 22,928; codified at 40 C.F.R. § 63.11956) 21

XIII. Stripped Resin 21

XIII.A. Grab Samples (77 Fed. Reg. 22,928–29; codified at 40 C.F.R. § 63.11960) 21

XIII.B. Site-Specific HAP List (77 Fed. Reg. 22,928; codified at 40 C.F.R. § 63.11960, Table 10) 22

XIV. Wastewater 22

XIV.A. Initial Determination (77 Fed. Reg. 22,930; codified at 40 C.F.R. § 63.11965) 22

XIV.B. Site-Specific HAP List (77 Fed. Reg. 22,930; codified at 40 C.F.R. § 63.11965, Table 10) 23

XIV.C. Maintenance Wastewater (77 Fed. Reg. 22,930; codified at 40 C.F.R. § 63.11965, Table 4) 23

XIV.D. Wastewater Compliance Reports (77 Fed. Reg. 22,933; codified at 40 C.F.R. § 63.11985, 

Table 4) 24

XIV.E. Process Wastewater (77 Fed. Reg. 22,940; codified at 40 C.F.R. § 63.12005) 24

XIV.F. Dewatering Equipment (77 Fed. Reg. 22,930, 22,940; codified at 40 C.F.R. §§ 63.11965, 

63.12005) 25

XV. Test Methods (77 Fed. Reg. 22,948; codified at 40 C.F.R. Part 63, Subpart HHHHHHH, Table 

10) 26