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> July 23, 2003

Air and Radiation Docket

US Environmental Protection Agency

Mail Code 6102T

1200 Pennsylvania Avenue, NW

Washington, D.C. 20460

Attn: Docket OAR-2002-0064

> RE: Protection of Stratospheric Ozone: Listing of Substitutes for
> Ozone-Depleting Substances -- n-Propyl Bromide, FR Vol. 68, No. 106,
> June 3, 2003
>
> Albemarle would like to comment on the Environmental Protection
> Agency's recently published Notice of Proposed Rulemaking for n-Propyl
> Bromide (nPB). The proposed rulemaking would list nPB as an acceptable
> substitute for ozone-depleting substances, subject to use conditions,
> in the solvent cleaning sector and aerosol solvents and adhesive end
> uses under EPA's Significant New Alternatives Policy (SNAP) program.
> Included in the proposal is a recommended workplace acceptable
> exposure limit (AEL) of 25 ppm as a time weighted average. We would
> like to commend EPA on the ( extensive ) effort that has gone into
> this rulemaking.

EPA has requested specific comment on the following:

> \[1\] Is it appropriate for EPA to find nPB acceptable for use in the
> solvent metals, electronics, and precision cleaning, aerosol solvents
> and adhesives, coatings and inks sectors? Why or why not? Should EPA
> have different decisions for different sectors or end uses? In
> particular, given that the CERHR Expert panel expressed concern about
> "poorly controlled spray adhesive applications," should EPA find nPB
> acceptable, subject to use conditions, for use in spray adhesives?
> Should the Agency find nPB acceptable, subject to use conditions, for
> use in aerosol solvents, or should nPB's use be limited to certain
> applications in this end use?

Albemarle has supported the use of nPB in applications where workplace
practices can control worker and atmospheric exposures. The majority of
our customers use nPB-based solvents in metal and electronic cleaning.
Our industrial hygiene program for nPB-based solvents has conducted
extensive air sampling and work place practice evaluation for customers.
The majority of the samples have shown values well below 25 ppm. In
those few workplaces with higher levels on initial sampling, adoption of
recommended workplace ventilation and handling practices produced
acceptable subsequent sampling values. Thus, our experiences with our
customers' worksites, as well as in our own plants, have also shown that
exposures can be controlled to protective levels.

As to other applications, ICF evaluated four different occupational
scenarios for spray adhesives and showed that improved work practices in
this highly emissive application can control worker exposures below the
recommended AEL.[^1] We agree with this evaluation -- with adequate
handling procedures, exposures can be controlled

> \[2\] What is an appropriate and achievable limit on the content of
> isopropyl bromide (iPB) in unstabilized nPB? Should this impurity
> limit be 0.1%, 0.05%, or 0.025% iPB by weight? Why? How much does each
> of these impurity levels add to the cost of cleaning solvents or
> adhesives made using nPB? In terms of \$/drum, and as a percentage of
> current cost?

We agree that a level of 0.05 % iPB in unstabilized nPB is an
appropriate and achievable limit. In fact, since 1996, Albemarle's
product specification for isopropyl bromide has been 0.03% maximum. We
do not know what it would cost per drum for a company not already using
this specification to change.

> \[3\] What is an appropriate acceptable exposure limit for EPA to
> recommend and why? If you disagree with the proposed exposure limit of
> 25 ppm, why do you disagree? Should EPA consider risk management
> principles in developing a recommended AEL? Please cite specific
> points of concern (e.g. studies considered, endpoints considered in
> BMD analysis, uncertainty factors applied?)

Albemarle agrees with EPA that an acceptable exposure limit for nPB is
25 ppm as a TWA, as long as skin exposures are also controlled. We have
previously supplied EPA with our derivation of that value as an AEL. The
recommended acceptable exposure limit derived by EPA used very
conservative scientific processes and additional uncertainty factors are
not needed for this value to be protective- even in highly emissive
applications such as adhesives.

\[4\] Should nPB be listed acceptable with a skin notation?

Yes, a skin notation should be made for nPB. Appropriate handling
practices for nPB contain measures for preventing skin exposure.

> We support EPA's decision that nPB should receive SNAP approval.
> Evaluation of atmospheric modeling concluded that atmospheric effects
> of NPB are more favorable than continued use of methyl chloroform, and
> that modeled exposure for the general population from use of NPB even
> in adhesive applications fall below a protective reference
> concentration. We are not aware of any new peer-reviewed data that EPA
> should consider for this rulemaking.
>
> Sincerely,
>
> R.L. Smith

#  Director, Product Stewardship

> Health, Safety and Environment Department

[^1]: "Risk Screen on the Use of Substitutes for Ozone-Depleting
    Substances; Proposed substitute: N-Propyl Bromide; End Use: Adhesive
    Applications" obtained from the EPA Air Docket (A-2001-07 II-A-13,
    May 17, 2002).