@Jpr Department of Pesticide Regulation

 

Paul E. Heltiker Governor
Director A Winston H. Hickox

Secretary. California
Enwronmrent?ali
Protection Agency

TO: Tobi Jones, Assistant Director
Ron Oshima, Assistant Director 
Doug Okumura, Assistant Director

FROM: Paul Gosselin
Acting Chief Deputy Direct
(916) 445?4330

DATE: April 9, 2001
SUBJECT: MANAGING (TELONE) CHRONIC RISKS

In 1990, based on monitoring data indicating elevated air concentrations of toxicological
concern, the Department of Pesticide Regulation (DPR) advised the county agricultural
commissioners to suSpend use of 1,3-Dichlor0propene (telone). After extensive interagency
review, in 1995, DPR authorized the limited reintroduction of 1,3?Dichloropropene. The
reintroduction required the use of a variety of control measures coming in the form of amended
pesticide labels, restricted materials permit conditions and registrant controls on distribution and
use. Strict county acreage limitations and a mandatory three year rotation of use on ?elds were
key to limiting exposure in light of the oncogenic risk.

Since the original reintroduction, the main regulatory control measure involved limiting the
amount of 1,3?Dichloropropene use in a geographic area (township) on an annual basis. The
township cap was chosen as a regulatory tool to manage exposure. The unavailability. of other
fumigants has increased the popularity of 1,3-Dichlor0propene as an alternative. In a number of
townships, the cap on annual use has or will be reached. This has prompted a number of affected
grower groups and the registrant to request relief from the township cap limit. We agreed to
deve10p guidance so the registrant could re?ne the exposure assessment for Speci?c townships

The purpose of this memorandum is to establish the acceptable risk level for 1,3?
DichlorOpropene risk in preparation of this guidance. We will set the acceptable oncogenic
lifetime (70 year) risk at 1 10'5 at the 95th percentile.

For townships facing or potentially facing the cap limit, have staff prepare guidance necessary
for the registrant or others to estimate the exposure of the Speci?c townships. Provided that the
anticipated annual air levels do not exceed a risk of 10? at the 95th we may authorize the
appropriate adjustment of the 1,3-Dichloropr0pene use for the Speci?c township(s). The
decision to adjust the current township cap must be based on written staff review of the exposure
assessment submitted by the registrant and recommendations from you.

Setting this acceptable risk level will require a review of the current td?wnship cap. For the time 0
being, we will maintain the current township cap as documented in the permit guidance.

Ct

1001 I Street - P.O. Box 4015 - Sacramento, California 95812-4015 - 
{5 A Department of the Catifomia Environmental Pmtection Agency