Growing up in the 1970s, Mischief Night was a big deal for me.  When I was in grade school, hoards of us kids took to our neighborhood just after dark to wreak innocent havoc.  More fun than Halloween, I recall soaping up car windows and decorating neighbors' trees with toilet paper.  (What were our parents thinking?)

When a wonder toy called Silly String hit the stores, Mischief Night turned psychedelic with crazy vibrant colors issuing in long streams from an aerosol can!  And what was the harm?  Silly String simply dried up and blew away.  Who knew that we might actually be spewing a brew of toxic chemicals? 

Polyisobutyl methacrylate, hexabromobenzene, dibutyl phthalate, dimethyl siloxane, dichloromethane and sorbitan trioleate.  While the current formulation of Silly String is claimed to be confidential business information, these are some of the ingredients in the product's original formula.  This, according to a fun little fluff piece that ran in a recent issue of Chemical & Engineering News titled “Silly String: It’s a party for polymer chemistry, all in a can.”

Some of these chemicals — hexabromobenzene (a brominated flame retardant), dibutyl phthalate (an endocrine disruptor) and dichloromethane (also known as methylene chloride, a carcinogen) — ought to rank high on anyone's list of chemicals of concern.

But am I just being a killjoy when I ask why we should be letting our kids play with this stuff?

I don’t think so, and here is why:  While thousands of synthetic chemicals are integral parts of our modern lives, this does not mean that any chemical can and should be used in any product.  In particular, how chemicals like the ones I just noted are used should get intense scrutiny, to say the least.

It may be that some of the offending chemicals are no longer used in the current Silly String formula – but that's something we don't know because its maker is allowed to claim such information proprietary.  It may be that some of the toxic chemicals used to make the polymer fully react, so that they aren't present in the Silly String itself, at least in normal use – but we can’t know this either, because no one requires such testing for residuals.

Whatever the risk, I would still assert the following:

• Chemicals with such clear toxicity should not be used in children’s toys.  Period. 
• Workers should not have to risk being exposed to such chemicals for the purpose of making toys.
• Society should not have to risk having such chemicals released into the environment as a consequence of making toys, whether during the chemicals' or product's manufacture or transport or after disposal of the product itself.

The C&E News article highlights an unplanned and highly novel use of Silly String:  Soldiers in combat zones have learned to spray it ahead of themselves when in confined spaces to help detect the presence of deadly trip wires.  Another possible future use is as an adhesive for medical use. 

Those potentially life-saving applications for this admittedly nifty polymer technology certainly call for a different calculus, where the outcome could be quite different than for its use as a children’s toy.  (I'm not suggesting, however, that the hazards of such uses should not also be scrutinized, or that safer alternatives not be identified or sought.) 

But the problem is that, at this point, no one is even bothering to do the calculation.  It is telling that the obvious questions as to whether this use of these kinds of chemicals might pose a risk to kids, or whether it is worth taking any such risk, were not even raised by the article's author.  Nor does our current chemicals management system effectively raise them, let alone demand they be answered.

This "silly" example is yet another reminder of why EDF believes we must fundamentally reform the law that governs how we manage these kinds of chemicals.

As I noted in our first post on ChAMP, after getting off to a strong start in 2007, EPA's abrupt decision in 2008 to steer ChAMP in the direction of cranking out hasty risk decisions was entirely its own.  Can ChAMP be put back on track? 

Neither EPA's own advisory committee – which had many members from the chemical industry as well as a few environmental NGOs – nor the commitment made by the U.S. under the North American Security and Prosperity Partnership (SPP) agreement signed with Canada and Mexico in August 2007, called for such risk assessments or risk-based prioritizations. 

The commitment EPA made under the SPP agreement was "to assess and initiate needed action on the over 9,000 existing chemicals produced above 25,000 lbs/yr in the United States."  There was no mention of risk assessment anywhere in the agreement.  Indeed, at that time, EPA had already begun to publish hazard characterizations, which, as assessments of the hazards of high production volume (HPV) chemicals – fully meet the terms of its SPP commitment.

EPA's focus on developing HPV chemical hazard characterizations was also precisely what it had committed to do when it adopted, in November 2005, the recommendations of its own National Pollution Prevention & Toxics Advisory Committee (NPPTAC).  Specifically, it agreed to complete and make public such hazard characterizations on all HPV chemicals for which it had received final data sets from the HPV Challenge – some 1,200 chemicals – within four years.

How close is EPA to meeting that commitment, with only six months to go?  As of today, EPA has issued only about 130 hazard characterizations covering about 315 HPV chemicals (many of the chemicals are in categories).

So EPA's rush to risk is not only resulting in flawed risk decisions that are prematurely exonerating hundreds of chemicals, as described in our earlier posts.  It is also causing EPA to renege on its promise to characterize the hazards of all sponsored HPV chemicals in a timely manner – and to clearly identify gaps in the quality and completeness of the data received under its voluntary program.

In short, EPA is compromising the public's right to know about the hazards of the most widely used chemicals in U.S. commerce.  That's quite ironic when you consider EPA bills the HPV Challenge and ChAMP as cornerstones of its Chemical Right to Know Initiative.

What should EPA be doing under ChAMP?

EDF is the only environmental NGO that has been willing to engage with EPA, first on the HPV Challenge and more recently on ChAMP.  We served on advisory panels, participated in public meetings, carefully peer-reviewed draft assessments, filed comments and met with EPA staff repeatedly. 

Even now, we are the only voice in our community arguing that the HPV data and ChAMP could provide value if it got back on track.

We have pointed out that many of the shortcomings of the HPV and ChAMP initiatives are due to EPA's limited authority under the Toxic Substances Control Act (TSCA), and we are actively working toward fundamental reform of TSCA to give EPA the tools it needs to do a better job.

But we also believe that in the interim, and despite EPA's constraints under TSCA, EPA can and should be doing a more credible and valuable job under ChAMP. 

EPA should:

• Return the focus of ChAMP to completing high-quality hazard characterizations for HPV chemicals, rather than rushing to issue highly suspect risk characterizations based on flawed assumptions and poor-quality use and exposure information.
• For each chemical assessed, clearly identify and communicate to the public all gaps or quality concerns in available data.
• Stop assigning low-priority rankings to chemicals, especially those with data gaps in the most basic, minimum set of screening-level hazard data. As we said before, it's one thing for EPA to identify as high-hazard those chemicals where, despite the data gaps, available data demonstrate high toxicity. It's quite another for EPA to effectively exonerate chemicals as low-hazard or low-priority when not even a bare-minimum data set is available for them.
• Adopt a health-protective approach to hazard screening: Where data are uncertain, of questionable quality or equivocal, assume a hazard exists until and unless a chemical's manufacturer provides the data to show otherwise.
• Issue test rules to require that gaps in submitted data sets be filled.
• Significantly accelerate issuance of test rules for all of the unsponsored HPV Challenge chemicals, and for the hundreds of newly emerged HPV chemicals that have never been sponsored.
• For the ~4,000 medium-production volume (MPV) chemicals – which are also covered by the SPP commitment, and for which even less data are available than for HPV chemicals – focus on identifying and acting to address data needs to support more robust hazard assessments, rather than pursuing its current approach of using scientifically unsupportable extrapolations of data among loosely defined "clusters" of such chemicals.

For chemicals for which significant hazards are identified, here are some of the good recommendations that NPPTAC offered as steps EPA could take even under its current TSCA authorities, which EPA has yet to act upon (under each, I've added a few elaborations and additional thoughts of my own in brackets):

• Gather additional information on uses (e.g., by use function, category, release potential, or benefit) and exposure (to humans and/or the environment).
  • [Listing such substances on the Toxics Release Inventory would be a great way to get direct exposure data. Efforts to get better use and exposure information - well beyond the data EPA got from manufacturers under its Inventory Update Rule (IUR) - could extend to downstream users of chemicals. Information on functional use would help in identifying safer substitutes within the same functional class.]
• Gather additional information on hazards to support a more in-depth characterization.
  • [Our reviews of EPA's risk decisions have identified many cases where available studies raise more questions than they answer, or identify additional concerns. EPA should require further testing in such cases.]
• Identify existing risk management programs and practices. Evaluate existing Federal and State regulatory controls (e.g., occupational exposure limits).
  • [Instead, in many cases EPA merely asserts the existence or effectiveness of such practices, and seems particularly averse to even suggesting that some risk management might be needed.]
• Provide information referrals or recommendations for actions to other EPA program offices or other Federal or State agencies.
  • [These could include referrals to OSHA requesting action on chemicals posing high worker hazards, proposing that the Centers for Disease Control or the U.S. Geological Survey add such chemicals to their biomonitoring and surface water monitoring programs, referring chemicals to its own Design for Environment (DfE) program to assess the availability and safety of available alternatives to hazardous chemicals, and referring such chemicals to the Food and Drug Administration where they have uses or are in consumer goods that fall under its jurisdiction.]

That's more than enough to keep the EPA toxics office busy for the foreseeable future.

This post is the first of a number to come that will examine in some detail specific chemicals and chemical categories for which EPA has made questionable or flawed risk decisions under ChAMP. Many of these problems can be traced to EPA's near-exclusive reliance on incomplete or poor-quality data provided by manufacturers, or its need to resort to unsupported assumptions in the absence of sufficient data. For each posting, we'll summarize what is known about production and use of the chemical(s); describe EPA's hazard, exposure, risk and priority rankings; and then discuss why we question or disagree with EPA's decisions. First up: a category of three alkyl nitriles.

The alkyl nitriles category is comprised of three chemicals: propionitrile (CAS# 107-12-0), butyronitrile (CAS# 109-74-0), and isobutyronitrile (CAS# 78-82-0). Their annual production volumes range from 3 to 30 million pounds. EPA's 2006 Inventory Update Rule data list a single producer for each chemical; other companies may have claimed their identity to be confidential business information (CBI):

According to EPA based on data supplied by their manufacturers, these chemicals are used primarily as chemical intermediates in the manufacture of insecticides, other industrial chemicals and pharmaceuticals. However, other industrial uses as catalysts, dielectric fluids and solvents were also reported, as well as possible use of one of the chemicals as a gasoline additive. EPA states that no commercial or consumer uses of these chemicals have been reported by their manufacturers. Two of the chemicals, propionitrile and isobutyronitrile, are regulated as Extremely Hazardous Substances under the Clean Air Act.

Hazard rankings: Although these chemicals are not persistent or bioaccumulative, EPA found that they are toxic following repeated dosing and can cause developmental defects. As a result, EPA classified these chemicals as highly hazardous to human health. In contrast, EPA ranked these chemicals as low hazard to aquatic organisms, based on testing results in fish, invertebrates and aquatic plants submitted by the manufacturers.

Exposure rankings: EPA concludes that environmental exposures will be low even if there are releases, because the chemicals would rapidly break down. Information submitted by manufacturers under EPA's Inventory Update Rule (IUR) did not indicate any commercial or consumer uses, including in products intended for use by children. EPA relies on this information to conclude that exposures to consumers and children are low. Other evidence beyond the IUR suggesting uses in pharmaceuticals and gasoline is not considered by EPA in making these rankings. EPA ranks worker exposure potential as high, as these are volatile chemicals that could readily partition to air, if not contained.

Risk rankings: Despite the high hazard ranking, EPA's risk conclusions emphasize the anticipated low exposure to characterize human health risks for the general public, consumers and children as low. EPA ranks the potential risk to workers as high.

Prioritization ranking: Despite finding both high human health hazard and high potential exposures and therefore risks to workers, EPA considers the alkyl nitriles category to be of low priority. EPA bases this ranking primarily on the existence of a National Institute for Occupational Safety and Health (NIOSH) recommended exposure limit (REL), which EPA claims if implemented would manage risks to workers.

Why We Disagree:

1. EPA has no basis to assume that the mere existence of the NIOSH recommended exposure limit for one of these chemicals means that it is being used or complied with. The REL is not a regulatory standard and EPA provides no empirical evidence whatsoever to indicate the extent to which it is being met in workplaces handling these chemicals. EPA itself states the reason why RELs should not be considered in ranking exposure: "these limits are not enforceable" (emphasis added; see p. 16 of EPA's Methodology for Risk-Based Prioritization Under ChAMP). Yet it then proceeds to reduce the priority of a category of highly hazardous chemicals to low on that very basis!

Likewise, EPA invokes the mere existence of a NIOSH/International Program on Chemical Safety (IPCS) International Chemical Safety Card for a second of the three chemicals and a NIOSH recommendation for establishing a workplace exposure standard for nitriles – a recommendation issued in 1978 that has never been acted on by OSHA! – as justification its low-priority ranking.

2. While we agree that the human health hazard posed by alkyl nitriles is high, we question EPA's low ranking for eco-hazard. Readily available data not referenced by EPA, which we quickly found via a simple Google search, indicates that both NIOSH and the International Program on Chemical Safety (IPCS) indicates that at least two of these chemicals may be ecotoxic: one may be hazardous to birds (butyronitrile), and another to aquatic organisms (proprionitrile).

In contrast, EPA appears to have relied solely on data submitted by the manufacturers of these chemicals, despite the fact that IPCS is listed as one of the supplemental sources EPA claims to search for hazard data (see Appendix B of EPA's Methodology document). For at least one of these chemicals, proprionitrile, EPA clearly knew of the existence of the IPCS document – because it (selectively) cited its mere existence as a basis for its low-priority ranking (see point 1 above).

The extent of ecological hazard is an issue that needs to be resolved, not ignored as will result from EPA's low-priority ranking for these chemicals.

3. EPA gives too much credence to the unsubstantiated use and exposure information provided by manufacturers. For two of the three chemicals, EPA has publicly provided a description of the industrial processing information supplied by the manufacturer under the IUR; for the third, that information was provided to EPA but claimed to be confidential. By accepting the limited use information provided under the IUR at face value, EPA assumes that 100% of production goes into use as intermediates. Yet EPA cites evidence from other sources suggesting other uses of these chemicals.

4. EPA bases most of its low-exposure findings on the fact that alkyl nitriles are used primarily as intermediates to make other industrial chemicals as well as pesticides and pharmaceuticals. Yet EPA fails to provide any data or even to discuss the potential for the final products to contain unreacted starting chemical (termed "residual" though the amounts can be significant). If present, the final product could be a source of exposure to the starting chemical.

While industrial chemical products made using alkyl nitriles are regulated under TSCA, EPA points out that pharmaceutical and pesticide products are not. Regardless, all sources of exposure to TSCA-regulated chemicals used as intermediates – including via residuals present in products – need to be considered. There is no mention of the nature of the products produced or how they are used. Exposure potential to such residuals in pharmaceuticals is obvious. For pesticides, worker and environmental exposures can be expected, and if approved for residential use, consumers applying the pesticides and children playing nearby could be exposed as well.

Exposure to residuals of the highly hazardous alkyl nitriles in products may or may not be significant, but EPA's silence on this question effectively means it has simply ignored it and assumed that there will be no or low exposure via this route. And its final prioritization decision relegating this chemical to low priority effectively closes the book on such questions.

5. EPA uses its exceedingly weak exposure characterization to justify the decision to assign low human health risk rankings for the general public, consumers, and children. This could readily result in underestimating risk, rather than taking a health-protective approach, which is the appropriate outcome of a screening-level risk characterization.

As a consequence of the hasty risk decisions made by EPA, important questions regarding the actual risks posed by these chemicals will not be answered: Could environmental organisms really be harmed? Are there residual levels of these chemicals in consumer products? Are workers adequately protected?

Some months ago, my colleague John Balbus posted here about studies finding that when multi-walled carbon nanotubes (MWCNTs) are injected into the abdominal cavities of mice, they induce inflammation and mesothelioma-like reactions similar to those caused by asbestos.  He appropriately cautioned that – among other critical questions – these studies had not demonstrated that inhaled MWCNTs could actually move out of the lung and into the tissues where asbestos gives rise to its effects.  Well, that particular dot now appears to have been connected.

We learned about the new findings via a blog post by Liz Borkowski at The Pump Handle.  She noted a disturbing item on the NIOSH blog posted by Vince Castranova and his colleagues late last week, in which they are seeking to share more broadly results they first presented at the recently-concluded Society of Toxicology meeting in Baltimore.

The NIOSH researchers reported new data showing for the first time that MWCNTs can migrate intact from the alveoli out of the lungs of mice and into the pleura, the tissue surrounding the lungs.  And it is in the pleura (as well as the abdominal cavity) where asbestos induces its signature form of cancer, mesothelioma.

In this case, the MWCNTs were introduced into the lungs using pharyngeal aspiration, a procedure by which mice are induced to inhale a droplet of liquid in which the MWCNTs are suspended.  While this procedure is thought to mimic direct inhalation, the NIOSH researchers note this and other limitations of the study, and caution that the results are preliminary and have not yet been peer-reviewed.

They also note that it's possible that the mice used in the study are unique and may not accurately portray what would happen in people, say, workers exposed to MWCNTs.  And, as my colleague pointed out in his earlier post, whether sufficient material could or would be suspended in the air to result in inhalation exposure also remains an open question.

Nonetheless, these new findings strongly suggest that, like asbestos, MWCNTs behave as stable fibers capable of penetrating and migrating through the lung.  And together with the earlier studies showing that introducing MWCNTs into the tissues surrounding the lung induces mesothelioma-like reactions, it's fair to say the alert level on MWCNTs just went up significantly.

Since my first post concerning EPA's Consent Order, I've been reflecting further on the management conditions it imposes – or, more accurately, on what conditions it doesn't impose.  The Order's only such conditions address potential worker exposure.  What about the rest of the nanomaterial's lifecycle?

The need to consider the full lifecycle and the full range of potential release and exposure pathways is a basic tenet of sound and responsible management of nanotechnology.  That's the backbone of the EDF-DuPont Nano Risk Framework, and it's also a key principle in EPA's own Nanotechnology White Paper and Nanotechnology Research Strategy.

Yet the Consent Order lacks conditions to address any potential releases or exposures beyond requiring gloves and other personal protective equipment for workers handling the nanomaterial.

Remember, the Consent Order notes that no test data were included in the producer's premanufacture notification (PMN).  On what basis, then, has EPA concluded that no other potential risks exist?  What about potential releases:

• from the manufacturing facility to the ambient air or water?
• from disposal or other management of wastes?
• from downstream transport, storage or processing?
• from post-use management (e.g., aging, weathering, repair, recycling) and disposal of products (electronics, polymer composites) containing the nanomaterial?

Nothing in the Consent Order addresses these questions – not, for example, a requirement to test products for potential releases, not even provisions to require reporting of waste management information or measurement or monitoring of releases.

Now, it may be that EPA has somehow managed to fully evaluate these and related questions and has determined that all of these risks are – and will remain, no matter what quantity of the nanomaterial is produced and used in the future – negligible.  If so, it should disclose how and on what basis it did so. 

EPA's failure to make public the decision framework it uses to evaluate new chemical submissions for nanomaterials – something we and other stakeholders have been requesting for some time – is a major impediment to building public trust in its process.

EPA's only bite at the apple

Some might argue that all this is premature and that EPA should wait until manufacture and use of this nanomaterial has ramped up even to consider such questions.  But here's the problem with that:  Under TSCA, the PMN review and conditions imposed through the Consent Order are essentially EPA's only bite at the apple.

Once Swan Chemical commences manufacture of its multiwalled carbon nanotubes (MWCNTs), they will be listed on the TSCA Inventory and will no longer be a "new" chemical.  At that point, anyone may manufacture and use the substance without even having to notify EPA.  And no matter what the quantity of the nanomaterial being produced and used, no further review by EPA would be triggered.

It should be noted that EPA is likely developing a Significant New Use Rule (SNUR) to accompany this Consent Order, and there are hints of that in the Order itself.  But all that a SNUR will do is to extend the same conditions that apply to the submitter of the PMN to other producers; it would require them to notify EPA only if they don't comply with these conditions.

Should a concern later develop about some other type of release or exposure not addressed by the Order and SNUR, EPA's only recourse would be to seek to use its authority under TSCA Section 6 to regulate the MWCNTs as an "existing" chemical – something EPA was unable to do, ironically, even for asbestos.  Yet that would be the only way that EPA could impose further conditions on production, processing, use, distribution or disposal of this nanomaterial.

Absent reform of TSCA to provide EPA with greater authority to regulate "existing" chemicals, EPA's new chemical review is, practically speaking, the only chance to ensure that potential risks across a new substance's full lifecycle are addressed.  An examination of EPA's Consent Order suggests that this opportunity has been lost for this nanomaterial.

[Part II of this post is available here.] 

Word hit the street today that EPA intends to make public a "sanitized" version of a Consent Order it has negotiated with a producer of multiwalled carbon nanotubes (MWCNTs).  [A link will be provided once available.]  We obtained a copy of the Order, which has redacted all information claimed confidential by the company involved.  What can we learn from this well-scrubbed Order?

The Order was triggered by EPA's review of a premanufacturing notification (PMN) – which, of course, is only required of companies producing the subset of nanomaterials EPA has decided to regard as "new."  This is the first public glimpse, albeit limited, into both EPA's thinking and its regulatory approach to "new" nanomaterials. 

EPA redacted the name of the company that has agreed to this Order – even though a simple Google search revealed that it almost certainly is Swan Chemical, Inc., of Lyndhurst, NJ.  That's because the company recently issued a press release announcing the Order.

So what does the Order call for?  The company is to:

• conduct a 90-day inhalation toxicity test in rats;
• supply EPA with a 1-gram sample of its MWCNTs and its Material Safety Data Sheet;
• submit certain characterization data within 6 months after commencing full manufacture;
• require its workers to wear protective gloves and clothing shown to be impermeable and NIOSH-approved respirators;
• use the substance only for a particular use, claimed confidential but generically identified as a "property modifier" in electronics and polymer composites; and
• provide the nanomaterial only to entities that agree to the same use restrictions and worker protection conditions.

Given recent evidence that MWCNTs can behave biologically rather like asbestos, such measures are more than called for.

But what's equally interesting are the details, including those that are missing from the sanitized Order because they were deemed confidential:

• The inhalation toxicity study doesn't need to be submitted before manufacture commences, but rather 14 weeks before either:  a) manufacture reaches a level of [BLEEP] kilograms, or a period of [BLEEP] years and [BLEEP] months after manufacture passes, whichever comes first. 
       From this, it's not at all clear:  a) why such details are secrets, and b) just how long it will be before the study is submitted.
• Adding to this mystery, the clock doesn't even start clicking on the time limit until two years after the Order is signed.
• The Order notes that no – zero, none, nada – test data were submitted with the company's PMN.
       This is actually not unusual for PMNs that come in under the Toxic Substances Control Act (TSCA), since EPA cannot require development and submission of such data up front, even for conventional chemicals. 
• Despite this lack of data, the Order states that EPA has determined that no significant environmental effects are expected.  Given how little environmental data exist on nanomaterials in general, let alone this particular MWCNT, it's hard to imagine how EPA reached this conclusion.
• The Order does state that "EPA is unable to determine the potential for human health effects" from exposure to this nanomaterial, and hence that it "may present an unreasonable risk of injury to human health."
       Presumably this is because of those recent findings that MWCNTs may act like asbestos.

So, to summarize these last two points:  Only if EPA already has evidence of a potential effect can it conclude that it is unable to determine whether there is an effect and call for testing.  If EPA doesn't have evidence of a potential effect – even if it has no data at all – it's ready to conclude that no significant effects are expected.  Welcome to life under TSCA!

Other very interesting tidbits:

The Order encourages the company to sign up for the in-depth phase of EPA's voluntary Nanoscale Materials Stewardship Program (NMSP), stating that if it does, EPA may waive the Order's requirement to conduct an inhalation toxicity test.  We can only wish that EPA gets something more than a non-binding commitment from the company to do some testing before vacating the Order!

Assuming the Order stays in place, if EPA finds the results of the required study to be "equivocal," the company can expand production beyond the production limit.  (I won't even discuss the perverse incentive this provision could create.)  Only if the company wants to get out from under the Order's other requirements (the use restriction or the worker protection provisions) need it reconduct the study.

What if the test results are invalid?

The Order appears to state that, if EPA finds the test data to be invalid, the company cannot expand production.  But there's a catch:  If there's not enough time to reconduct the study and submit it 14 weeks before exceeding the production limit, then the company can go ahead and exceed the limit as long as it submits the study "within a reasonable period of time."  The company can also exceed the production limit if it challenges EPA's determination that the data are invalid in writing.

If the company decides the test data are invalid before submitting them to EPA, as long as it informs EPA of this determination, EPA can still decide to allow expanded production.  As before, if EPA does decide to require the company to reconduct the study, but there's not enough time to reconduct and submit it 14 weeks before exceeding the production limit, then the company can go ahead and exceed the limit as long as it submits the study "within a reasonable period of time."

What if the test results show significant risk?

The Order states that if EPA determines that the data are valid and unequivocal and indicate the nanomaterial "will or may present an unreasonable risk," EPA may but is not required to notify the company, and may but is not required to impose additional conditions.  If EPA does issue such a notice, the company must either comply with the new conditions or cease production, use and distribution.  But again there's a catch:  If the company challenges EPA's determination in writing, it can continue these activities while the dispute is resolved.

All these allowances for the very type of nanomaterial that is #1 on just about everyone's concern list.

[UPDATE:  It should be noted that the above allowances are actually fairly standard practice for new chemical consent orders and are not limited to those issued for nanomaterials; indeed, EPA has developed "boilerplates" for its consent orders that contain very similar language.]

I have been among those calling on EPA for greater transparency in how it assesses new nanomaterials.  This is a step in the right direction in that regard.  But I have to say that getting this glimpse at EPA's inner workings doesn't exactly bolster my confidence in what they're doing.

Andrew Maynard, of the Project on Emerging Nanotechnologies, recently blogged about an Australian study that documented an odd effect of sunscreens containing nanoscale titanium dioxide (TiO2).  The study was prompted by the observation that installers of metal roofs who used these sunscreens inadvertently transferred the product onto the roofs. In places where the workers’ skin had touched the painted metal surfaces, the paint showed accelerated weathering. Why?  Because the particular type of nanoscale TiO2 in the sunscreen (the anatase crystal form) is photoactive – when it absorbs UV light, it releases free radicals that speed up the oxidation of the underlying paint.

So it’s only fair to ask whether the use of such sunscreens could accelerate the weathering of our skin.  Andrew says not necessarily.  While the observed damage to roof paint raises a red flag, for harm to our skin to occur would require that the free radicals penetrate down to the living layers of the skin.  That step has not (yet) been observed to occur. 

Researchers from DuPont noted that some but not all forms of nanoscale TiO2 exhibit such photoactivity.  And reactivity can be decreased (or increased) by introducing special treatments and surface coatings to either “passify” or activate such materials. 

One might have expected that sunscreen formulators would choose to use the less-reactive nanoscale TiO2.  So why do some of these sunscreens exhibit increased photoactivity?  Does this demonstrate a lack of understanding on the part of formulators, or are treatments used to reduce reactivity breaking down over time?   And is the government watching? 

So let’s review what we know and don’t know:
• We know that some forms of nanoscale TiO2 are more reactive than others.
• We know that nanoscale TiO2 can be modified to reduce reactivity.
• We know that some sunscreens that contain the more reactive form of nanoscale TiO2 can damage painted metal roofs.

But:
• We don’t know if frequent use of sunscreens containing the more reactive form of nanoscale TiO2 poses a greater health (or environmental) risk than the less reactive form.
• We don’t know what type of nanoscale TiO2 is present in any given sunscreen we may purchase (in fact we may not even know if the TiO2 is nanoscale or not).
• There’s still a lot more research needed to determine whether each of the various forms of nanoscale TiO2 can or cannot penetrate skin, including actively flexed or damaged (e.g., sunburned) skin.

Meanwhile, be careful climbing on that roof!

Ah, summer!  It’s a great time to be outdoors, enjoying the warm, sunny weather.  Before you go outside, be sure to grab your sunscreen, that essential product that protects against skin cancer and sun damage.  But which kind of sunscreen is best?  There is a mesmerizing array of sunscreen options, but for our purposes let’s limit the question to one:  Nano or not nano?

We all recall the white noses of the beach lifeguards.  The zinc oxide or titanium dioxide in these nose-protecting potions form a thick, white barrier that blocks damaging ultraviolet (UV) radiation by reflecting and scattering light.  These days, nanoscale titanium dioxide and zinc oxide are increasingly popular sunscreen ingredients, as they provide a UV barrier but are nearly transparent.

One of the concerns raised by using nanoscale titanium dioxide and zinc oxide in sunscreens is the dearth of safety data on potential health that could arise from applying nanoscale minerals to the skin on a daily basis – including to skin that may be damaged (e.g., already sunburned).  The sunscreens are then released into lakes or oceans, or washed down the drain with the bathwater with unknown environmental effects.

First, it must be pointed out that the same concern – lack of adequate safety data — applies to many of the traditional chemical sunscreen ingredients.  Nanoscale materials may require additional scrutiny, however, because their properties can differ from their bulk-scale counterparts.

Some environmental advocacy groups, such as Friends of the Earth, citing the lack of safety data and unclear product labeling, have called on the Food and Drug Administration to require more testing and exercise better regulatory oversight.  Meanwhile, because of these problems, Friends of the Earth ranks nanomaterial-containing sunscreens among the worst. 

In contrast, Environmental Working Group, while recognizing the critical data gaps, generally ranks sunscreens with nanoscale zinc and titanium oxides as having a lower hazard than those containing the most common active ingredients, such as oxybenzone and octyl methoxycinnamate.  As summarized by EWG, these non-nano ingredients are linked to a number of health hazards, including cancer and developmental and reproductive toxicity.  EWG argues that, in addition to being more effective, sunscreens made with nanoscale zinc and titanium oxides generally contain fewer hazardous ingredients overall. 

A range of opinions regarding nanoscale zinc and titanium oxides are available on popular websites, including Treehugger, Huffington Post, and the Green Guide.  The one thing everyone seems to agree on is that the lack of adequate safety data makes it hard to draw definitive conclusions regarding the safety of nanomaterials in sunscreens. 

The US Food and Drug Administration will soon be updating its “Sunscreen Monograph” – the regulatory document that specifies what chemicals can be used in sunscreen formulations, and in what concentrations.  This is a clear opportunity for FDA to be more proactive, by requiring that more data be developed to demonstrate sunscreen ingredient safety, and that more data be made publicly available so that consumers can make better-informed choices. 

In the meantime, if we are to avoid the real harm that over-exposure to the sun can cause, we have little choice but to select among sunscreen formulations — all of which contain insufficiently tested ingredients — hoping that whatever we do is better than the burn.

In the current regulatory environment, where there are no regulations that specifically take into account the unique properties of engineered nanomaterials, industry has by default the primary responsibility for their safe production and use. Is industry taking this responsibility seriously?

Two recent studies, one in Europe and one in the U.S., shed light on this question and reveal some reasons to be concerned.

Helland et al. (2008) distributed a written questionnaire to 135 companies in Germany and Switzerland. Forty companies completed the questionnaire (representing a 30% response rate). Interestingly, most respondents believed that there is a very low potential for direct exposure to or environmental release of nanomaterials throughout the life cycle of their nanomaterials (production, consumption, and disposal). Only four companies, however, reported having any actual data relevant to assessing these potentials.

Most of the respondents said they believe their current risk assessment procedures are sufficient to evaluate nanomaterials, and that safety measures currently in place are adequate. Yet sixty five percent of the companies completing surveys had not conducted any assessment of risk.

The results of this survey seem to indicate that, for many companies, something more akin to wishful thinking is currently substituting for actual data and risk assessments.

Similar results were obtained in a survey by Lindberg and Quinn (2007) of small – medium sized nanotechnology companies in Massachusetts, which found that, while the larger companies believe that they are managing risks appropriately, they are basing their assessments on very little data. Not only are smaller companies not addressing risks, but they are more likely to believe that risks are unlikely.

Helland et al. conclude that, in general, industry lacks a “systematic approach to assessing … risks.” Furthermore, they suggest that the limited attention paid to assessing risks may result in underestimating both hazard and exposure, and hence raise questions regarding the adequacy of the precautions that are being taken.

Happily, some guidance is emerging for companies to use in identifying, assessing and mitigating potential risks of their nanomaterials and associated products. The Nano Risk Framework, developed jointly by Environmental Defense and DuPont, is one example of a small but growing number of efforts to develop a systematic approach to assessing risks and offering recommendations for data development and decision making throughout the product lifecycle. The National Institute for Occupational Safety and Health and the British Standards Institute have also prepared information to help guide occupational exposure assessment and mitigation. These “how to” guides can help companies to steer clear of questionable assumptions that seem to form the current foundation of many industry assessments of nanomaterial risks.

While it can help, making guidance available is of course not sufficient to ensure companies actually assess and sufficiently address potential risks. Helland et al. conclude that “Developing proactive risk management strategies appears to be an urgent task for minimizing the risk of harm to the environment and the public health.” In light of industry’s positive self-assessment of its current risk management efforts, both the public and private sectors need to put in place mechanisms to ensure such efforts amount to more than merely wishful thinking.