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Comment 1: In the proposed SNUR, EPA clarified that it considers nanomaterials to include substances with a particle size less than 100 nanometers where d10 particle size presents the particle size as determined by laser light scattering at which 10 percent by weight of the substance measured is smaller. We support this approach based on the need for a threshold since solid particulate material will contain a distribution of particle sizes. The 10 percent threshold strikes a reasonable balance between being adequately protective of human health and recognizing practical limitations associated with analytical methods available for quantifying materials at or below such a threshold. We support using the weight

- based threshold, as methods and instrumentation for performi ng weight

- based particle size measurements are more widely available than techniques for performing measurements based on particle number. There are other important elements that should be included in any definition of a nanomaterial including recognizing that aggregates and agglomerates are not the same as the primary particles of which they are comprised and that many agglomerates may not disagglomerate readily in any medium.

EPA Response: In the proposed rule, EPA did not attempt to clarify what it c onsiders to be a definition of a nanomaterial, although particle size of less than 100 nanometers (nm) is often used to describe such chemical substances. Based on information contained in the PMNs, EPA believes that the PMN submitter is not manufacturing or processing the PMN substances with a d10 particle size less than 100 nm. EPA also believes it is possible that these chemical substances could be manufactured or processed with a d10 particle size less than 100 nm. EPA proposed a new use in the SNURs f or these two PMN substances to require notification if those chemical substances were manufactured or processed with a d10 particle size less than 100Summary of Comment Responses for PMNs P

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- 1075 June 2012 nanometers. Upon notification of this new use, EPA would review the properties and assess any potential r isks that were different from the chemical substances as reported in the PMNs. While EPA believes that the threshold and method used to measure particle size for these PMN substances is appropriate and protective of human health, EPA will consider differen t thresholds and methods in other TSCA actions, depending on the chemical substances being measured and available scientific knowledge and technology.

Comment 2: The PMN substances are not nanoscale substances and any concerns or regulatory requirements derived from concerns related to nanoscale materials are not pertinent to the PMN substances.
EPA Response: As described in the consent order, the basis for EPA’s concern for the PMNs, is not whether the substances constitute nanoscale materials but rath er the fact that they qualify under the new chemicals category for respirable, poorly soluble particulates, under the subcategory of titanium dioxide. ( See http:// w ww.epa.gov/opt/newchems/ pubs/ chemcat.htm .) The category document identifies that t here is po tential for respirability if workers handle material containing any particles less than or equal to 10 microns in diameter . Based on information in the PMNs, workers are likely to be exposed to particles less than or equal to 10 microns in diameter. In addition , b ased on information contained in the PMNs, EPA believes that manufacturers and processors could use these chemical substances at particle sizes less than 100 nm. Accordingly, EPA has proposed new uses that would enable EPA to review any manufact ure or processing of the PMN substance without the use of appropriate respiratory protective equipment or engineering controls, or at particle sizes less than 100 nm. The purpose of these notificationsSummary of Comment Responses for PMNs P

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- 1075 June 2012 (i.e., SNUNs) is to allow EPA to review any new proper ties and assess any potential risks presented by the new use.

Comment 3: EPA’s risk assessment stated there is no exposure expected to the PMN substances, according to the Human Health Effects Summaries in the Consent Order. EPA determined that there can be no risk warranting regulation under the proposed rule, because of the statement that no absorption of the PMNs is expected via any route of exposure if the PMN substances are produced via the calcination method. The PMN substances can only be manufactu red using the calcining process and there is no known alternative industrial process for making chemical substances such as the PMN substances. Based on review of EPA’s risk assessment and the extensive experience of industry members with similar products, there is no substantiation of potential risk in the record for the proposed rule or the necessity for any regulation of the PMN substances.

EPA Response: The Human Health Effects Summary, contained in Unit IV. (“EPA’s Assessment of the Risk”) of the Con sent Order does not address potential exposures to the PMN substances; workplace inhalation exposures are addressed in a separate Exposure Summary of the same Unit IV. The health effects summary does state, however, that if the PMN substances are calcined then EPA does not expect the PMN substances to be absorbed by any route of exposure. In addition, the health effects summary identifies concerns for potential lung effects from exposure to the PMN substances, according to the chemical category for respirab le, poorly soluble particulates under the subcategory of titanium dioxide. ( See http://w ww.epa.gov/opt/newchems/ pubs/ chemcat.htm
. ) There is concern for the potential lungSummary of Comment Responses for PMNs P

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- 1075 June 2012 effects when workers handle material containing particles less than or equal to 10 mi crons in diameter
. Based on information in the PMNs, workers are likely to be exposed to particles less than or equal to 10 microns in diameter. The concern for lung effects is not mitigated by calcination; the concern is independent of potential for absor ption. In fact, because these insoluble particles are not absorbed, they remain in the lung longer than other particles, causing further inflammation and lung effects. As mentioned earlier in this response, the Exposure Summary in the consent order identif ies potential inhalation to workers. Based on the potential hazard and exposure to workers, EPA concluded that the PMN substances may present an unreasonable risk of lung effects to exposed workers.

Comment 4: EPA should clarify that the PMN substances a re not salts. It is incorrect for EPA to characterize these chemical substances as salts. EPA’s health risk analysis based on structural analogs does not demonstrate a risk warranting regulation because the regulated substances do not exhibit the propertie s of the constituent metals and do not represent an unregulated dust exposure. Titanium dioxide is not an analog surrogate for the PMN substances. EPA’s assessment should evaluate the risk of the finished crystal form of the PMN substances.

EPA Response: EPA is not characterizing the PMN substances as salts or metals, and the structural analogy in the consent order was not based on analogy to salts or constituent metals. EPA’s structural activity relationship (SAR) analysis was based on the category of re spirable, poorly soluble particulates that cause lung effects as a result of inhaling particles. ( See http://w ww.epa.gov/opt/newchems/ pubs/ chemcat.htm
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. Titanium dioxide was chosen as the subcategory based on its physical characteristics as a poorly soluble particulate, and not anySummary of Comment Responses for PMNs P

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- mediated toxicological properties. T he risk assessment, as described in the response to the comment 3, is consisten t with the Agency’s concerns that potential exposure to particles of the finished crystal form of the PMN substances may cause an unreasonable risk of lung effects.

Comment 5: EPA relied on a recommended exposure level (REL) from the draft National Insti tute for Occupational Safety and Health ( NIOSH) Current Intelligence Bulletin: Occupational Exposure to Titanium Dioxide as the source of the proposed NCEL of 1.5 mg/m 3

. Since the final NIOSH intelligence bulletin set a higher REL of 2.4 mg/m 3 , EPA should revise its risk assessment to incorporate this new information.

EPA Response: EPA agrees that using the REL of 2.4 mg/m 3 for titanium dioxide, from the final NIOSH bulletin, would be more appropriate. This document is located in the docket under docket ID number EPA

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- 1075. In fact, paragraph (b)(2) of the New Chemical Exposure Limit of the consent order for the PMN substances contains an automatic sunset clause stating that the NCEL in the consent order would automatically and immediately be changed to the final REL for titanium dioxide issued by NIOSH. Accordingly, EPA will issue the final SNURs with a NCEL of 2 .4 mg/m 3 , based on the final NIOSH REL for titanium dioxide. However, because EPA estimates that there are potential exposures greater than 2.4 mg/m 3 , EPA continues to find a potential risk of concern for the PMN substances.

Comment 6: T hese chemical sub stances are subject to existing Occupational Safety and Health Administration (OSHA) Permissible Exposure Levels (PELs) for inorganic tin compounds. Given the existing applicable OSHA PELs, the proposed SNURs are duplicative andSummary of Comment Responses for PMNs P

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- 1075 June 2012 unnecessary regulation. The NCELs provisions in the 5(e) orders state that the NCEL and respirator requirements are automatically nullified if OSHA promulgates a PEL for the same substance. There is a separate OSHA standard, applicable to all inert dust particles, of 5 mg/m 3

. There is no need for EPA to require the development of additional and different regulatory monitoring techniques for the PMN substances because there are already analytical monitoring techniques developed for inorganic tin compounds and inert dust particles.

EP A Response: While the OSHA PEL for inorganic tin compounds would be applicable to the inorganic tin contained in the PMN substances, it does not apply to the PMN substances themselves. Based on information submitted in the PMNs, EPA considers the substanc es to be mixed metal oxide compounds. Other comments make the argument that the constituent metals are not bioavailable and there should not be concern for exposure to bioavailable metals from the PMN substances. EPA is not characterizing the PMN substance s as metals and the basis of its risk assessment is not the constituent metals contained in the PMN substances. See EPA’s response to comment 4. While there is an OSHA inert dust standard of 5 mg/m 3 , EPA finds there is still a potential risk for lung effec ts from exposures less than 5 mg/m 3 for the PMN substances. Paragraph (b)(2) of the New Chemical Exposure Limit of the consent order for the PMN substances does state, that if OSHA promulgates a PEL specifically applicable to the PMN substances then the re spirator requirements and NCEL become null and void. This paragraph (b)(2) also states that the requirements of the consent order are not negated by any pre

- existing OSHA PEL, such as the PEL for inorganic tin compounds cited by the commenters. Because OSH A has not promulgated a PEL specifically applicable to the PMN substances, the respirator requirements and NCEL requirements in the consent order for the PMN substances remain inSummary of Comment Responses for PMNs P

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- 1075 June 2012 effect. Neither the PMN submitter nor commenters have supplied any informatio n on whether existing monitoring techniques used for inorganic tin compounds would be appropriate for use with the PMN substances. EPA has issued the consent order and will issue the final SNURs with the NCEL provisions to allow for review of any monitorin g techniques for the PMN substances that would be used to demonstrate compliance with the exposure limits.

Comment 7: The costs and economic impacts of the rule are underestimated significantly. Customers may not use the PMN substances because of compli ance costs. Manufacturers of the PMN substances will incur costs as a result of complying with the SNUR requirements, and costs associated with submitting a significant new use notice, including submitting toxicological testing prior to manufacture or impo rt of the PMN substances for a significant new use.

EPA Response: The economic assessment developed by EPA for this rule estimates and discusses the potential costs identified by the commenter. The commenter did not supply any additional information disp uting EPA’s specific cost estimates or conclusions. Therefore, EPA will not change any of its cost estimates or conclusions. Contrary to the commenter’s assertions, the SNURs do not require testing, and submission of a SNUN does not require submission of t oxicological testing. The preamble to the proposed SNURs did recommend testing that could address potential risks EPA has identified for the PMN substances, and states that SNUN submitters can submit any other data to address potential risks. Anyone submit ting a SNUN is strongly encouraged to submit information addressing potential risks, but specific testing is not required.Summary of Comment Responses for PMNs P

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Comment 8 : EPA’s economic assumptions pursuant to the Regulatory Flexibility Act do not reflect the current market. Nearly identical structural analogs of the PMN substances already on the TSCA Inventory are produced by companies in the United States and abroad. The PMN substances are produced abroad and imported in finished articles.

EPA Response: The commenter did not supp ly any information on present or future significant new uses by small or large entities of the substances subject to the SNURs. Therefore, the basis for EPA’s finding under the Regulatory Flexibility Act, that the promulgation of the SNURs will not have a significant adverse economic impact on a substantial number of small entities, will remain unchanged in the final rule.

Comment 9: The rule would prevent U.S. manufacturers from manufacturing and using the PMN substances in finished products while the ru le would not prevent the use of the PMN substances outside the United States. Foreign manufacturers of finished products containing the PMN substances will be able to use the PMN substances and import them as part of articles exempt from TSCA reporting.

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PA Response: TSCA primarily addresses risks within the United States. The Consent Order and the SNURs do not prevent U.S. manufacturers from manufacturing and using the PMN substances in finished products. In fact, the Consent Order negotiated with the PM N submitter allows manufacture, subject to certain restrictions. Those restrictions are reflected in the SNURs. The SNUR s exempt all manufacturers and processor s from significant new use reporting onceSummary of Comment Responses for PMNs P

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- 1075 June 2012 the PMN substance s have been incorporated into a polym er, glass, dispersion, cementitious matrix, or a similar incorporation. This includes articles imported into the United States. For these uses, no significant exposures are expected. The Consent Order and the SNURs would only be applicable in the United St ates to manufacturers or processors of the PMN substances in particulate form. EPA issued the Consent Order and is issuing the SNURs to address potential worker exposures associated with manufacture and processing of the PMN substances that could result in a risk of lung effects.

Comment 10: There are economic and environmental benefits identified in the PMN submissions for these chemical substances. Specifically, the PMN substances are intended to replace pigments containing heavy metals such as lead and cadmium which are associated with risks to human health and the environment.

EPA Response: While EPA agrees that it would be beneficial to replace pigments that contain lead and cadmium, EPA found that the potential unreasonable risks associated with th e PMN substances warranted issuing a consent order and significant new use. Comment 11: EPA received one comment opposing the approval of the use of 2,4

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