EPA Nano Authority under TSCA, Part 2: “New” Isn’t Necessarily All That Better

Richard Denison, Ph.D., is a Senior Scientist.

[Links to posts in this series: Part 1, Part 2, Part 3, Part 4, Part 5]

In my last post, I decried EPA’s shortsighted decision to declare nano forms of chemicals listed on the Toxic Substances Control Act (TSCA) Inventory to be “existing” rather than “new” chemicals.  But I noted that EPA did not rule that all nanomaterials are existing chemicals.  EPA says it will consider buckyballs, carbon nanotubes, or anything else that has no counterpart – a substance with the same chemical structure – already on the TSCA Inventory to be “new.”  So can we rest assured that, at least for these nanomaterials, EPA has sufficient authority under TSCA to effectively identify and address their potential risks?  Would it were so. 

I’ll cover below three main questions concerning how EPA’s new chemicals review process relates to nanomaterials.  First, will EPA even know that a new chemical it is reviewing is a nanomaterial?  Second, will available exemptions from new chemicals review allow nanomaterials to get a free pass?  And third, even when they are subject to new chemicals review, will nanomaterials get the scrutiny they need?  I’ll end this post with a note about transparency – or the lack thereof.

Will EPA even know a New Chemical Notification it receives is for a nanomaterial?

Under TSCA, a manufacturer of a new chemical is obliged to notify EPA prior to commencing production or import.  So the first question that arises is whether EPA would even know that a new chemical being notified is actually a nanomaterial.

The fact is that no such designation is required on the reporting form used for such notifications.  (An optional worksheet that can be included with a notification does include “particle size distribution” among other properties, so if a manufacturer chose to fill out and submit the worksheet, that could provide EPA with a clue.)  EPA says it has received several dozen new chemical notifications for nanomaterials, but has not indicated how many of these included an explicit identification of the substance as a nanomaterial.  Indeed, EPA staff say that in a number of cases its chemists have been able to “figure out” that a notification is for a nanomaterial in the absence of such designation.

All of this begs the question of whether or how often EPA has received new chemical notifications for nanomaterials that have not been identified as such – and hence has reviewed them without benefit of such knowledge.  It is baffling to me why EPA has not simply amended its notification form to make this identification mandatory and unambiguous.

Exemptions from new chemical notification requirements are unsuited to nanomaterials.

The new chemical notification required by TSCA can take the form of either a Premanufacture Notification (PMN), or a written request for an exemption from PMN requirements.  There are a number of such exemptions that EPA has developed, all of which are potentially available to nanomaterials.  Exemptions requiring notice and EPA approval prior to manufacture are those for test marketing (TME), low volume (LVE) and low release/low exposure (LOREX) situations.

TSCA provides two additional exemptions that don’t even require a manufacturer to notify EPA at all before commencing production or import.  These “self-implementing” exemptions are for R&D activities and for certain polymers.  (Bizarrely, a company making an exempt polymer must inform EPA after commencing manufacture that it has done so, but the letter need not even identify the polymer! (see answer to Question 304-1 in this EPA Q&A))  Clearly, EPA will have no idea whether a nanomaterial is being made if its producer determines it qualifies for either of these exemptions.

Over the years, EPA has developed criteria to identify chemicals eligible for the various exemptions from PMN requirements.  These criteria were designed with conventional chemicals in mind, so it is perhaps not surprising that they are either inappropriate or need to be revised for nanomaterials.

The low volume exemption (LVE) is available for any chemical manufactured in quantities equal to or less than 10,000 kilograms (22,000 pounds) per year.  For nanomaterials, this value raises several concerns:  First, a mass-based threshold fails to reflect the fact that a nanomaterial’s “potency” is often poorly represented by mass and should instead be expressed in terms of surface area, particle count or other such metrics.  Second, because many nanomaterials are indeed much more potent per unit mass – that is, they have a higher activity, reactivity, etc. – than their conventional counterparts, blindly applying the same threshold to both makes no sense.  Finally, a large proportion of current nanomaterial producers likely qualify for this exemption because their production falls below this effectively much higher threshold as applied to nanomaterials.

The low release/low exposure exemption (LOREX) is equally problematic.  EPA’s criteria for what constitutes “low” release or exposure are either mass-based (for exposure by inhalation or oral routes) or, for worker exposure, are based on the presumed effectiveness of engineering controls or personal protective equipment.  Yet there are widely acknowledged difficulties both in detecting and measuring nanomaterials in environmental media and the workplace, and in assessing the effectiveness of exposure controls in minimizing nanomaterial exposures.  And here again, many current producers of nanomaterials could well qualify for this exemption.

Upon receipt, EPA has 30 days to review and decide on these exemption requests.  EPA has authority to alter the terms of an exemption, but to do so EPA must show that the substance may cause serious acute or chronic health effects or significant environmental effects.  Given the novel properties of most nanomaterials and the dearth of information available on them, making this finding is likely to prove very difficult in practice.

Finally, there is the exemption for certain polymers.  This exemption is based on the presumed low bioavailability and toxicity of many conventional polymers, and is defined mostly through molecular weight considerations.  This approach assumes that polymers act as individual molecules.  Polymer nanoparticles behave differently, however, and some have been shown to be bioavailable as well as toxic (see, for example, here and here).  Continuing to apply the polymer exemption to nanomaterials, at the very least without revision, is unwarranted.

To date, EPA has expressed no inclination to tailor these exemptions to nanomaterials and has not even initiated a dialogue about revisiting them.  This, despite the fact that EDF and others have been calling on EPA to do so for nearly four years.  Our view is that, until and unless they are appropriately revised, nanomaterials should be ineligible for such exemptions.  Yet EPA is already granting the current exemptions to nanomaterials.

EPA’s time- and data-limited “one bite at the apple” for new chemicals is insufficient.

Two other major limitations affect EPA’s authority to effectively review and regulate new nanomaterials under TSCA.  For nanomaterials for which PMNs are submitted, EPA will typically have only a one-time, 90-day review opportunity.  Once reviewed and placed on the TSCA Inventory, any company can manufacture and use the nanomaterial without even having to notify EPA it is doing so.  The only exception is if EPA simultaneously issues a Significant New Use Rule (SNUR).   In that case, manufacturers proposing to make or use the nanomaterial outside of the terms specified in the SNUR would have to notify EPA.

Given the strong expectation that both the uses of nanomaterials and information available about them will be changing rapidly in the foreseeable future, an effective oversight system should be able to expediently revisit earlier reviews – something TSCA makes very difficult.

Finally – and perhaps most significantly of all – EPA is precluded under TSCA from requiring up-front submission of a minimum set of data on a chemical’s hazards.  This oddity of TSCA stands in contrast to the policies of virtually every other developed country in the world.  As a result, the majority of PMNs for conventional chemicals actually contain no hazard data (see page 8 of this EPA document and the answer to Question 118-5 in this EPA Q&A).  Even fewer data can be expected to accompany nanomaterial PMNs.

While this limitation applies to all new chemicals, the problem is enormously exacerbated with nanomaterials.  That’s because the estimation methods and models EPA has developed to compensate for this lack of data on conventional chemicals simply don’t work with nanomaterials.  Why not?  Because the models work by relating hazard data for a tested chemical to an untested chemical based on the degree of similarity in their chemical structures.  But nanomaterials’ properties are dictated much more by their physical structure and properties than by their chemical makeup.

EPA can request testing on a case-by-case basis, but only if it finds that the substance either:

i) “may present an unreasonable risk” (a finding EPA is rarely able to make without the data that testing would provide – a classic Catch-22), or
ii) is produced in substantial quantities and may result in substantial environmental release or human exposure.

In addition to the difficulty of making these findings – manifested in that fact that EPA has rarely required testing even for conventional chemicals – most of the criteria EPA has developed to define “substantial” entail yet more mass-based thresholds not appropriate for nanomaterials.

So, the bottom line is that even for the subset of nanomaterials EPA regards as “new” chemicals, EPA faces major constraints under TSCA in exercising effective oversight.

What ever happened to transparency?

All of the problems identified in this post are made worse by the extreme lack of transparency on EPA’s part as to the nature and extent of its review of new chemical notifications for nanomaterials, the decision-making process it uses and the regulatory outcomes.  EPA’s website contains only the vaguest of descriptions of these activities, unnecessarily obscuring what should be an opportunity for an open and frank sharing and exchange of information and understanding.

While I recognize that confidential business information concerns are often at play here, that should not preclude EPA from indicating how many reviews it has conducted, how often it has granted each type of exemption and on what grounds, and so on.  What possible purpose is served by not doing so?

Check back soon for my last post in this series, in which I’ll describe the even bleaker landscape facing EPA in regulating nanomaterials deemed to be “existing” chemicals under TSCA.

[Links to posts in this series: Part 1, Part 2, Part 3, Part 4, Part 5]