inorganic arsenicals Notice of Final Determination 11/93
Inorganic Arsenicals; Conclusion of Special Review
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of Final Determination; Conclusion of Special
SUMMARY: This Notice announces the conclusion of the Special
Review for the remaining non-wood preservative uses of the inorganic
arsenicals. In 1988, a Notice of Final Determination for most
of the non-wood uses was issued. In that Notice, EPA determined
to cancel several registrations for inorganic arsenicals, leave
two registrations in effect, and defer action on five remaining
uses. Four of the remaining five uses subsequently were canceled.
In 1991, the Agency proposed cancellation of the remaining use
- arsenic acid on cotton. Subsequently, these registrations
also were voluntarily canceled. Since there are no longer any
viable registrations for these five uses, EPA is concluding
the Special Review.
FOR FURTHER INFORMATION CONTACT: Ann Sibold, Special Review
and Reregistration Division (7508W), Environmental Protection
Agency, 401 M St., SW., Washington, DC 20460. Office location
and telephone number: Special Review Branch, 3rd floor, Crystal
Station Building #1, 2800 Crystal Drive, Arlington, VA. 22202.
This Notice concludes the Special Review of the five remaining
non-wood preservative uses of the inorganic arsenicals. The
Special Review of the inorganic arsenicals began on October
18, 1978, when EPA issued a Notice of Rebuttable Presumption
Against Registration (RPAR, now called a Special Review) (43
FR 48267) for the wood preservative and non-wood preservative
uses of inorganic arsenicals. The RPAR was triggered by the
finding that use of the inorganic arsenicals met or exceeded
the risk criteria for carcinogenicity, teratogenicity (developmental
effects) and mutagenicity (genetic effects).
1. Wood preservative uses. In 1981 (46 FR 13020), EPA proposed
changes to the terms and conditions of registration for the
wood preservative uses of inorganic arsenicals. These changes
were based on an assessment of the risks and benefits of continued
registration of inorganic arsenicals as wood preservatives.
The Final Determination, issued July 13, 1984, (49 FR 28666),
required certain modifications to the terms and conditions of
registration and concluded the Special Review for the wood preservative
uses of the inorganic arsenicals. Subsequently, EPA received
requests for hearings from registrants contesting the requirements
of that Notice. EPA considered registrants' suggestions for
reaching the goals of the July 13, 1984 Notice, and amended
the Notice of Intent to Cancel (51 FR 1334, January 10, 1986).
All registrants have either modified their registrations in
accordance with the Amended Notice or their registrations were
2. Non-wood preservative uses. On January 2, 1987, EPA issued
a Preliminary Determination proposing to cancel the registrations
of virtually all of the non-wood preservative uses (the ``minor''
uses) of inorganic arsenicals (52 FR 132). This action was based
on two risk concerns, acute toxicity and carcinogenicity. Acute
toxicity had been added as a risk concern after the Special
Review was initiated. It was based on a large number of accidental
poisonings, particularly of children. The Agency found that
the acute risks to children from accidental ingestion of arsenic
compounds outweighed the benefits. Carcinogenicity was found
to be a risk to workers handling inorganic arsenical pesticides.
The Agency found that protective clothing or a restricted use
classification would not reduce the risks to an acceptable level
in light of the limited benefits. EPA deferred consideration
of four inorganic arsenicals - the ``major'' uses, including
arsenic acid on cotton and okra, sodium arsenite on grapes,
calcium arsenate on turf, and lead arsenate on citrus-for the
following reasons. First, these uses did not pose acute risks,
and second, the Agency found it necessary to review further
the potential risk from dermal and dietary exposure. In 1988,
EPA issued a Final Determination to Cancel products containing
inorganic arsenicals for most of the minor uses of inorganic
arsenic (53 FR 24767). In this Notice, only two registrations
were retained: the insecticidal use of arsenic trioxide in a
sealed metal container and the solid formulation of arsenic
trioxide used to control moles and gophers. These uses were
retained because the products were packaged in a manner that
reduced chances of exposure, so that the benefits of continued
use outweighed risks. Finally, this Notice concluded the Special
Review of the non-wood preservative uses except for the deferred
uses. After a hearing requested by several registrants, an Administrative
Law Judge upheld the cancellations, and in July, 1989, that
determination was upheld by the Administrator.
The Agency subsequently took regulatory actions on the deferred
uses of the inorganic arsenicals as discussed below.
On October 19, 1990, EPA announced receipt of a request to
voluntarily cancel a registration of lead arsenate used as a
growth regulator on citrus (55 FR 42445). EPA stated the cancellation
would become effective December 18, 1990 unless EPA received
a request to withdraw the cancellation during the comment period.
No such request was received. The cancellation became effective
January 22, 1991. The Registrant could sell existing stocks
until October 19, 1991. Existing stocks in the hands of dealers
and users could be sold and used until exhausted. Tolerances
were revoked April 3, 1991 (56 FR 13593). The revocation took
effect before the end of the last sales date set in the cancellation
order because the Agency believed that all but untreated commodities
had cleared the channels-of-trade by the end of 1990.
In a letter dated March 15, 1989, EPA canceled a registration
of calcium arsenate on turf at the registrant's request. The
registrant was permitted to sell existing stocks until February
28, 1990. Existing stocks in the hands of dealers and end users
could be sold and used until December 31, 1991.
On June 19, 1991, EPA announced that it had received a request
for voluntary cancellation of the registration of sodium arsenite,
a fungicide, on grapes (56 FR 28154). EPA also established a
comment period to allow any interested party to have the registrations
transferred. No requests for transfer were received. Thus, on
January 13, 1992, EPA canceled the registrations (57 FR 1262).
The registrant was allowed to sell and distribute existing stocks
until January 13, 1993. All others were allowed to sell and
use existing stock until supplies were exhausted. The tolerance
was proposed for revocation in 1992 (57 FR 1244), and became
final on July 22, 1993 (58 FR 39153). The effective date of
the revocation is June 30, 1994.
Arsenic acid was also registered as a desiccant on okra grown
for seed under the authority of section 24(c) of FIFRA. In 1989,
the registrant requested voluntary cancellation from the state.
The state allowed sale and use of existing stocks until November
In 1991, EPA announced its preliminary determination to cancel
the registration of arsenic acid as a desiccant on cotton (56
FR 50576). The risk case was based on unacceptable cancer risks
to workers exposed to arsenic, which is classified as a known
human (Group A) carcinogen. The Agency concluded that these
risks were not amenable to mitigation and were not balanced
by the benefits to growers. In addition, while not a basis for
initiating the Special Review, the Agency considered groundwater
contamination a potential source of exposure. EPA further concluded
that there were no practical protective measures to adequately
mitigate exposure. Other matters addressed by EPA included:
(1) A proposal to prohibit the sale and use of existing stocks
because the benefits associated with allowing time to sell and
use existing stocks were judged to be limited and not justified
when weighed against risks.
(2) A proposal to conclude the Special Review of all other
non-wood preservative pesticide products containing inorganic
(3) A comment period which was later extended to June 5,
1992, at the request of several commenters (57 FR 3755, dated
January 31, 1992).
EPA transmitted copies of the PD 2/3 to the Secretary of
Agriculture and the Scientific Advisory Panel (SAP) for comment.
The SAP met on June 25, 1992, to review the scientific issues
in the PD 2/3. The SAP and the Department of Agriculture's comments
are summarized in this Notice. In addition, they are printed
in full in the Support Document for the Conclusion of the Special
Review together with EPA's response. This Support Document may
be found in the public docket as described in Unit VI of this
After the comment period closed, the registrants Elf Atochem
North American (Atochem) and Voluntary Purchasing Groups (VPG)
initiated discussions with the Agency regarding voluntary cancellation
conditioned upon provision for sale and use of existing stocks
through the 1993 use season. On May 6, 1993, (58 FR 26975),
EPA announced receipt of voluntary requests from these registrants
of arsenic acid to cancel their registrations of arsenic acid
use on cotton. The cancellations were made effective immediately.
In the cancellation order, EPA permitted existing stocks to
be sold until October 31, 1993. Growers are permitted to use
existing stocks until December 31, 1993. Registrants will buy
back stocks (in unopened containers) remaining after the 1993
use season. A discussion of the reasons for the change in the
provision for sale and use of existing stocks may be found in
Unit IV of this notice.
Subsequently, EPA found that Drexel Chemical Company also
had a viable (although suspended) registration for arsenic acid
cotton desiccant. After being contacted by EPA regarding this
registration, Drexel requested voluntary cancellation, and notice
of this action and the cancellation order was published in the
Federal Register on July 22, 1993, (58 FR 39205).
The tolerance for arsenic acid on cottonseed was proposed
for revocation on September 22, 1993 (58 FR 49267). With these
actions, EPA completed review of the last inorganic arsenical
in Special Review.
3. Conclusion of Special Review (PD4). In the PD 2/3 for
arsenic acid on cotton (56 FR 50576), EPA set forth its risk/benefit
determination for this use. After reviewing the comments received
in response to the PD 2/3, EPA found no new information that
would cause a change in the risk/benefit determination for arsenic
acid on cotton. EPA's review of the comments, reconsideration
of the risks and benefits of the registrants' proposal to permit
the sale and use of existing stocks, and final determination
regarding Special Review of arsenic acid on cotton are set forth
in this document.
In addition, the PD 2/3 also proposed that the special review
be concluded for lead arsenate on citrus, calcium arsenate on
turf, sodium arsenite on grapes, and arsenic acid on okra grown
for seed. The Agency's final determination regarding Special
Review of these uses is set forth in this document.
II. Summary of Risk Determinations and Agency Evaluation of
Comments and Additional Data
A. Hazard Characterization
In the PD 2/3 for arsenic acid (56 FR 50576), EPA discussed
in detail the data on the carcinogenicity of arsenic. Arsenic
is a known human (Group A) carcinogen, for which a dose-response
relationship has been calculated for the inhalation and oral/dermal
routes of exposure. The SAP reviewed and agreed with the risk
characterization of the PD 2/3. Their comments are included
in full in the Support Document. EPA received no other comments
on the hazard characterization of arsenic. Thus, EPA has not
revised the hazard characterization set forth in the PD2/3.
B. Exposure and Risk Assessment
In the PD 2/3, the Agency discussed the basis for its estimates
of the levels of inhalation and dermal exposure for workers
handling arsenic acid. The PD 2/3 displays in tabular form the
Agency's conclusions regarding levels of exposure and risk for
different occupations and different geographical regions where
arsenic acid is applied. Estimates of excess upper bound risks
ranged from 10.-2 to 10.-7. In addition, the Agency calculated
levels of potential exposure and risk for residents living in
the vicinity of cotton gins. The estimated excess upper bound
risk was estimated at 10.-3. EPA also found that there was a
potential for arsenic to contaminate groundwater. The SAP reviewed
and agreed with the risk characterization of the PD 2/3. The
USDA comments did not specifically address the exposure and
risk assessment of the PD 2/3. The Agency received several other
public comments on its exposure case. These comments questioned
exposure measurements for closed cabs, mixer/loader exposure,
pilot exposure, ground-water concerns, the definition of a ``normal''
work year for harvesters, the use of the Pesticide Handlers
Exposure Database (PHED), estimates of risk to area residents,
and regulatory jurisdiction over cotton gin workers. Commenters
submitted some new data relating to enclosed cab exposure, but
noted that the limited data could not support a regulatory decision.
EPA carefully considered these comments. However, neither
the comments nor the new data received could demonstrate that
EPA's exposure estimates should be revised. Thus, EPA has not
changed its exposure estimates or its risk case. A detailed
discussion of the comments and the Agency response are available
in the Support Document.
III. Summary of Benefits Assessment and Agency Evaluation of
Comments and Additional Data Received
In the PD 2/3, EPA estimated that affected growers could
lose in aggregate as much as $19 to $22 million per year as
a result of the cancellation of arsenic acid. EPA received a
number of comments on the benefits assessment. The most important
general criticism was that EPA did not adequately assess the
ripple effect on the local community if many growers left the
cotton business. EPA carefully considered these comments. However,
none of these comments contains data or specific information
that would prove that EPA's estimate of benefits is greatly
understated. Thus, EPA does not find it necessary to revise
its benefits case. A detailed discussion of the comments on
the benefits assessment of the PD 2/3 and EPA's response may
be found in the Support Document.
In addition, the PD 2/3 was sent to the Secretary of Agriculture.
The USDA/National Agricultural Pesticide Impact Assessment Program
(NAPIAP) estimated losses ranging between $14 and $52 million,
based on USDA and State assessments. They noted that EPA's estimate
of $19 to $22 million was toward the lower end of their range.
They noted the variability of arsenic acid use based on earliness
EPA carefully considered these comments. However, because
the comments contained no data or details of how USDA made its
estimates, EPA cannot evaluate their soundness. Thus, EPA does
not feel its estimate is necessarily too low. EPA is well aware
of the variability in frost dates from information contained
in the Inorganic Arsenicals Assessment Team Report of 1980,
and took this variability into account in developing its benefits
assessment. These comments are considered in more detail in
the Support Document.
IV. Summary of Existing Stocks Provisions and Agency Evaluation
of Comments and Additional Data Received
In the PD 2/3, EPA proposed to prohibit the sale, distribution,
and use of existing stocks of arsenic acid after the final date
of cancellation because risks outweighed the localized benefits.
EPA received several comments both supporting and opposing this
position. Several commenters opposed a prohibition on sale and
use of existing stocks because the severe local economic impact
could be eased by a phaseout. Other commenters supported the
prohibition on sale and use of existing stocks because waste
treatment costs resulting from processing arsenic acid treated
cotton were unreasonably high. EPA considered these comments,
but did not find them persuasive.
However, with regard to the registrants Atochem and VPG,
EPA has determined to allow the sale and use of existing stocks
of arsenic acid products through the 1993 use season because
this action achieves the most favorable risk/benefit determination.
The comments, EPA response, and EPA's decision is discussed
in detail in the May 6, 1993 Notice of Voluntary Cancellation
(58 FR 26975) and in the Support Document.
V. Comments of the Scientific Advisory Panel and the Secretary
As required under Sections 6 and 25 of FIFRA, the Agency
provided the PD 2/3 and technical support document to the Scientific
Advisory Panel and the Secretary of Agriculture. Their comments
and the EPA responses are summarized in Units II and III of
this notice. In addition they are printed in full in the Support
Document along with the EPA response.
VI. Risk/Benefit Assessment and Decision Regarding Special Review
Prior to 1991, the Agency had completed the review of the
inorganic arsenicals, including wood preservatives, and most
non-wood preservatives except for five uses of arsenic acid,
sodium arsenite, lead arsenate, and calcium arsenate. In the
PD 2/3 for arsenic acid, the Agency proposed to conclude the
Special Review of four of these uses, including the use of arsenic
acid as a desiccant on okra grown for seed, sodium arsenite
as a fungicide on grapes, lead arsenate as a plant growth regulator
on grapefruit, and calcium arsenate as a herbicide on turf,
leaving only arsenic acid as a desiccant on cotton remaining
in Special Review. In today's notice, the Agency has responded
to the comments received on the PD 2/3 for arsenic acid as a
cotton desiccant, and the Agency has determined that it will
not modify the risk/benefit assessment of arsenic acid on cotton,
which was set forth in the PD 2/3. Further, the registrants
have requested voluntary cancellation of their registrations
for arsenic acid on cotton, and EPA has canceled them. Sale
and use of existing stocks of Atochem and VPG arsenic acid cotton
desiccant products will end after the 1993 use season. Therefore,
the Agency is concluding the Special Review for the remaining
non-wood preservative uses of the inorganic arsenicals: lead
arsenate growth regulator on citrus, calcium arsenate on turf,
sodium arsenite fungicide on grapes, and arsenic acid on okra
VII. Public Docket
Documents referred to in this Notice, including the Support
Document, may be reviewed at the Public Docket (OPP-30000/29B),
located at Room 1132, CM #2, 1921 Jefferson Davis Highway, Arlington,
Virginia 22202. The Docket is open from 8:00 a.m. to 4:30 p.m.,
List of Subjects
Dated: November 24, 1993.
Lynn R. Goldman,
Assistant Administrator for Prevention, Pesticides and Toxic
[FR Doc. 93-29716 Filed 12-7-93; 8:45 am]