Out of
the frying pan …
Barbara Kanegsberg, BFK Solutions
I’ve rarely used hairspray; in part, because
I have never been a fan of aerosols, even for cosmetic or household use.
Releasing all those little
droplets always seems wasteful; and, as a biologist, I find inhaling them to
be unappealing. In contrast to the final rule listing n-propyl bromide (nPB)
as “acceptable” for cleaning, there is a second EPA SNAP
(Significant New Alternatives Policy Program) proposed rule impacting emissive
uses of nPB. The proposed rule would list nPB as an “unacceptable
substitute” for ozone depleting compounds in adhesives and aerosol
applications but does not address the overarching issues of chemicals for aerosols
and other emissive uses. In my opinion, the EPA is attempting to address an
overall process issue by disallowing one chemical. For too many manufacturers,
it would mean jumping from the frying pan to the fire. The proposed alternatives
to nPB have problems. Some are fiscally impractical; others have performance
issues; still others have other environmental/worker safety issues. It would
be far more productive for the EPA to withdraw this rule and instead revisit
the regulatory approach to all solvents, all solvent blends, and all
water-based blends when used in aerosol and other highly emissive applications.
Consider the nPB alternatives
The proposed substitutes for nPB may not be appropriate for your application.
In fact, many products that could be and are likely to be used are less
well characterized than nPB.
SNAP lists a host of substitutes determined to be acceptable or acceptable
subject to use conditions under the SNAP program including: water-based
formulations, alcohols, ketones, esters, ethers, terpenes, HCFC-141b,
HCFC-225ca/cb, hydrofluoroethers
(HFE’s), Hydrofluorocarbon (HFC) 4310mee, HFE-365 mfc, HFC-245fa, hydrocarbons,
trans-1,2-dichloroethylene, Methylene chloride, trichloroethylene, perchloroethylene,
and parachlorobenzotrifluoride (PCBTF). SNAP considers hydrocarbons, alcohols,
blends of trans-1,2-dichloroethylene (trans) and HFE’s or HFC’s,
and HCFC-225 ca/cb to be the most likely substitutes.
Alternatives – not better options
The alternatives do not represent an improvement relative to nPB in terms
of process costs and process quality. Quality includes product quality,
employee safety, and impact on the environment. The costs to change the
process may
be higher than indicated. For example, with flammable materials, depending
on your application and on other processes in the area, adding few flash
arrestors may not be enough to protect your workers, your property, or
your product.
Hydrocarbons and alcohols comprise a rather large category of organic compounds with high expected variability in terms of performance, toxicological profile, and environmental attributes. Flammability is an issue for many alcohols and hydrocarbons. If there is concern by the EPA about excessive worker exposure to process chemicals and the lack of adequate process controls, there might also be questions about the acute issues related to flammability. HFC’s and HFE’s are good carriers and flashpoint-inerting agents; they are exceedingly mild solvents. They are expensive. Trans is flammable, although it can often be flashpoint-inerted by blending with HFC’s, HFE’s, or HCFC-225. I would also like to see more detailed public disclosure and availability of the toxicological studies related to trans; and it would be helpful to see similar studies on the blends. The trans blends, by the way, tend to be more costly than other products; trans blends have been adopted for high-end, high-value production. HCFC-225 is not flammable, and it has been judged to have a good toxicology profile. It has solvency properties similar to chlorofluorocarbon-113 (CFC-113; Freon); it is relatively costly; and, because it depletes stratospheric ozone, it is scheduled for phase-out January 1, 2015.
Exposure studies
The proposed rule has summarized the toxicity profile of nPB. It is not
clear to me, however, how the profile of nPB compares with that of
other chemicals.
In addition, many of the workplace studies include additional variables.
The proposal includes extensive summaries of observed effects on
nPB in animal studies and occupational exposure studies, primarily
in processes
involving
application of adhesive using nPB as a carrier. A few preliminary
comments are appropriate.
There are at least two complications in evaluating the worker exposure
studies. The first is reproducing actual exposure conditions.
Based on our initial reviews,
and on indications in the proposed rule, worker exposure during adhesive
application can be very high. In at least one case, this was
due to grossly, highly unacceptable
chemical handling – the sort of behavior that is intolerable with any chemical
in any process. The second is the impact of other chemicals also used in the
vicinity. Chemical blends may have synergistic effects that result in better
cleaning, better coating, greater environmental damage, and/or higher overall
toxicity (please read TANSTAAFL in this issue of “Clean Source”).
Better controls for ALL emissive applications
The SNAP proposal discusses industry practices for aerosols and adhesives
and indicates the unlikelihood of controls that could adequately
manage nPB exposure.
I would propose a more optimistic, comprehensive approach.
About 3⁄4 of the way through the rule, EPA does indicate that they will
take comments about controls that are adequate for nPB even though they rejected
that idea in favor of proposing an outright “unacceptable.” The
reasoning becomes a bit clearer in the context of the rule. In any event,
the EPA is taking
comments on a scheme that would allow nPB aerosol usage ONLY if the companies
regularly monitor employees; and this usage would be allowed ONLY if exposure
for all employees falls below a certain level.
I do not think you should restrict your comments to the above
plan. Given what we do not know about chemicals and blends
used in aerosol
and adhesive
applications,
it is apparent that we need better controls no matter what
chemical or blend is adopted. This is why I suggest that the EPA
withdraw
the proposal
and
instead ask for approaches to controlling emissive use of all
solvents, solvent blends,
and aqueous products.
Coatings – proposed approval for a single facility
Apparently, one single military facility submitted a separate
request to the SNAP group to use nPB in their coating application.
They
submitted data
indicating
unacceptability of other options along with worker exposure
data. EPA is therefore proposing to allow nPB usage in coatings
ONLY
for the
one facility
and to require
other groups to submit separate SNAP applications whenever
they wanted to use nPB.
While I myself prepared a SNAP submission for aerospace applications
in the early 1990’s, such applications are far from the norm. Most industrial
and military groups would not even think about needing to submit separate
SNAP requests for
their applications. I also think it imposes quite a burden on small to
medium industries.
Speak up!
Read the proposed rule; see how it will impact your business.
Then, tell the EPA your views. As in all such public
issues, you want
to check with
your boss,
first. I also suggest hitting the “tact” key on the computer.
The EPA SNAP group has obviously put a great deal of thought and effort
into the
proposed rule. While no one know for sure, I feel rather confident in predicting
that lobbyists and advocates for various causes and technologies will make
their views known to the EPA. You should, too.
The SNAP Program website is at http://www.epa.gov/ozone/snap/ .
The Proposed nPB Rule document can be found at http://www.epa.gov/fedrgstr/EPA-AIR/2007/May/Day-30/a9706.pdf
For more about gross chemical mis-management, please
see “Working with
Newer Chemicals,” Green Files, volume 1, issue
1. http://sqrc.org/Newsletter%20Archive/Volume%201,%201/working%20with%20newer%20chem.html
