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Sulfur - Pesticide Reregistration 5/91

United States Environmental Protection Agency
Pesticides And Toxic Substances (H-7508W)
21T-1012 May 1991



Pesticide Reregistration

All pesticides sold or used in the United States must be registered by EPA,
based on scientific studies showing that they can be used without posing
unreasonable risks to people or the environment. Because of advances in
scientific knowledge, the law requires that pesticides which were first
registered years ago be reregistered to ensure that they meet today's more
stringent standards.

In evaluating pesticides for reregistration, EPA obtains from pesticide
producers and reviews a complete set of studies showing the human health and
environmental effects of each pesticide. The Agency imposes any regulatory
controls that are needed to effectively manage each pesticide's risks. EPA
then reregisters pesticides that can be used without posing undue hazards to
human health or the environment.

When a pesticide is eligible for reregistration, EPA announces this and
explains why in a Reregistration Eligibility Document, or RED. This fact sheet
summarizes the information in the RED for sulfur.


The element sulfur is a ubiquitous, natural component of the environment.
Currently, sulfur is registered by EPA for use as an insecticide, fungicide
and rodenticide on several hundred food and feed crop, ornamental, turf and
residential sites. It is also used as a fertilizer or soil amendment for
reclaiming alkaline soils. Sulfur is applied in dust, granular or liquid form,
and is an active ingredient in nearly 300 registered pesticide products. All
registered uses of sulfur are eligible for reregistration.

Regulatory History

Sulfur has been known and used as a pesticide since very early times, and has
been registered for pesticidal use in the United States since the 1920s. EPA
issued a Registration Standard for sulfur in December 1982. The only data
requirement imposed at that time was a proposal for crop reentry intervals. No
additional generic data have been required since then.

Health Effects

All of EPA's toxicology data requirements for sulfur have been satisfied for a
number of years. Sulfur is known to be of low toxicity, and poses very little
if any risk to human health.

     Acute Effects
Short-term studies show that sulfur is of very low acute oral toxicity and
does not irritate the skin (it has been placed in Toxicity Category IV, the
least toxic category, for these effects). Sulfur also is not a skin
sensitizer. However, sulfur can cause some eye irritation, dermal toxicity and
inhalation hazards (it has been placed in Toxicity Category III for these

     Chronic Effects
Chronic exposure to elemental sulfur at low levels is generally recognized as
safe. Epidemiological studies show that mine workers exposed to sulfur dust
and sulfur dioxide throughout their lives often had eye and respiratory
disturbances, chronic bronchitis and chronic sinus effects. However, no known
risks of oncogenic, teratogenic, or reproductive effects are associated with
the use of sulfur. Also, sulfur has been shown to be non-mutagenic in

Routes Of Exposure

We are all exposed to sulfur, since this element is ubiquitous in the
environment- Sulfur in its various forms represents about 1.9 percent of the
total weight of the earth. Most terrestrial and aquatic environments contain
high levels of sulfur.

     Through the Diet
People may be exposed to small amounts of sulfur through the food supply.
However, since sulfur does not pose any relevant toxic effects, no dietary
risk assessment was performed. Sulfur is generally recognized as safe, as
noted in 40 CFR 180.2(a), so no tolerances (or residue limits) need be
established for residues of sulfur in or on food or feed commodities.

     During Application
People can be exposed to sulfur while mixing, loading or applying the
pesticide, and while working among treated crops. Based on incidents of skin
and eye irritation reported among field workers in California, EPA has
determined that a hazard exists for workers reentering fields following foliar
application of sulfur dust. Therefore, a 24-hour reentry interval and
protective clothing requirements must be added to the labeling of all outdoor
use sulfur products.

Environmental Hazards

All the environmental fate and ecological effects data requirements are
satisfied for sulfur. This ubiquitous substance does not cause unreasonable
adverse effects in the environment when used according to approved labeling,
and poses little or no hazard to non-target organisms.

     Environmental Fate
In the 1982 Registration Standard, all environmental fate data requirements
were waived for sulfur based on the fact that it is a natural component of the
environment. The use of elemental sulfur as a pesticide or a soil amendment is
not an environmental concern because it becomes incorporated into the natural
sulfur cycle.

     Ecological Effects
In six studies on ecological effects (involving bobwhite quail, two fish
species, daphnia, mysid shrimp and honey bees), sulfur has been shown to be

practically non-toxic to the species tested. Thus, although there is potential
for non-target organisms to be exposed to sulfur, little hazard to these
species is expected to result.

Additional Data Required

The generic data base supporting the reregistration of products containing
sulfur has been reviewed and determined to be complete. No further generic
data are required to support reregistration. Some product-specific data are
being required as described in Appendix D to the Reregistration Eligibility

Product Labeling

All end-use outdoor sulfur product labels must bear an updated  Changes
Required  water contamination warning, and a 24-hour reentry statement and
protective clothing requirements to protect handlers and field workers from
adverse skin and eye effects. Please see the Reregistration Eligibility
Document for the exact wording of these required label - statements.

Regulatory Conclusion

- The studies available to EPA indicate that the element sulfur is of low
toxicity, and its use as a pesticide poses very little known hazard to people
and nontarget species.

- Sulfur dust can cause eye and skin irritation to people who handle the
pesticide or come into contact with treated foliage during field work.
Therefore, a 24-hour reentry interval and protective clothing requirements
must be included on all outdoor sulfur product labels.

- The pesticide sulfur can be used without causing unreasonable adverse
effects in people or the environment. Therefore, all pesticide products
containing sulfur as the sole active ingredient are eligible for

- EPA will reregister individual products containing sulfur once product
specific data and revised product labeling are submitted to and accepted by
the Agency.

For More Information

EPA is requesting public comments on the Reregistration Eligibility Document
for sulfur during a 60-day time period, as announced in a Notice of
Availability published in the Federal Register. To obtain a copy of the RED,
or to submit written comments, please contact the Public Response and Program
Resources Branch, Field Operations Division (H-7506C), Office of Pesticide
Programs, U.S. EPA, Washington, D.C. 20460, telephone 703-557-4436, or Fax
#703-557-1884. Please note that after the comment period closes, the RED will
be available from NTIS, at the address and telephone number below.

To obtain a copy of the December 1982 Registration Standard for sulfur, please
contact the National Technical Information Service (NTIS), 5285 Port Royal
Road, Springfield, VA. 22161, telephone 703- 487-4650. Request document #PB86-

For more information about sulfur or about EPA's pesticide reregistration
program, please contact the Special Review and Reregistration Division (H-
7508W), Office of Pesticide Programs, U.S. EPA, Washington, D.C. 20460.