Department of Pesticide Regulation Logo

Paul E. Helliker Director

Department of Pesticide Regulation

  California Notice 2001-2

California State Seal
Gray Davis

Winston H. Hickox
Secretary, California
Protection Agency

July 1, 2000 THROUGH December 31, 2000

California regulations require the Department of Pesticide Regulation (DPR) to investigate all reports of actual or potential significant adverse effects to people or the environment resulting from the use of pesticides. If an adverse impact occurred or is likely to occur, the regulations require DPR to reevaluate the registration of the pesticide.

Title 3, California Code of Regulations (CCR), section 6221, specifies the factors under which DPR may initiate a reevaluation: (a) public or worker health hazard, (b) environmental contamination, (c) residue over tolerance, (d) fish or wildlife hazard, (e) lack of efficacy,
(f) undesirable phytotoxicity, (g) hazardous packaging, (h) inadequate labeling, (i) disruption of the implementation or conduct of pest management, (j) other information suggesting a significant adverse effect, and (k) availability of an effective and feasible alternative material or procedure that is demonstrably less destructive to the environment. Often, ongoing DPR reviews trigger a reevaluation. Reevaluation triggers also include state and county pesticide use surveillance and illness investigations, pesticide residue sample analyses, environmental monitoring activities, and information from other state or federal agencies.

When a pesticide enters the reevaluation process, DPR reviews existing data. DPR requires registrants to provide additional data to determine the nature or the extent of the potential hazard or identify appropriate mitigation measures, if needed.

DPR concludes reevaluations in a number of different ways. If the data demonstrate that use of the pesticide presents no significant adverse effects, DPR concludes the reevaluation without additional mitigation measures. If additional mitigation measures are necessary, DPR places appropriate restrictions upon the use of the pesticide to mitigate the potential adverse effect. If the adverse impact cannot be mitigated, DPR cancels or suspends the registration of the pesticide product.

This report complies with the requirements of CCR section 6225. CCR section 6225 requires DPR to prepare a semiannual report describing pesticides evaluated, under reevaluation, or for which factual or scientific information was received, but no reevaluation was initiated. The report contains two sections:

I. Formal Reevaluation - initiated when an investigation indicates a significant adverse impact has occurred or is likely to occur (page - 2); and

II. Preliminary Investigations (Evaluations) - products or active ingredients for which DPR receives possible adverse, factual, or scientific information, but no reevaluation has been initiated (page - 6 ).

I. FORMAL REEVALUATION - undertaken when investigations indicate that a significant adverse impact has occurred or is likely to occur.

BRODIFACOUM - 33 Products

Brodifacoum is registered in California to control rats and mice in residential, industrial, commercial, agricultural, and public buildings. Registrants formulate the product with a grain-based bait in pellets, mini-pellets, and wax blocks.

On December 30, 1999, at the request of the Department of Fish and Game (DFG), DPR placed pesticide products containing brodifacoum into reevaluation. DFG expressed concern that California's wildlife are exposed and adversely affected by currently registered uses of the anticoagulant rodenticide brodifacoum.

Since 1994, DFG's Pesticide Investigations Unit has investigated 58 cases of possible wildlife exposure to anticoagulant rodenticides. Residues of anticoagulant rodenticides were detected in 38 birds and mammals, and residues of brodifacoum were identified in 31 birds and mammals, accounting for 82 percent of the anticoagulant exposures. Of the 31 individuals in which residues of brodifacoum were detected, clinical signs of anticoagulant poisoning were observed in 10 to 20 percent. Eleven of the animals also carried residues of at least one other anticoagulant rodenticide in conjunction with brodifacoum. Because wildlife typically retreat to dens, burrows, or unobtrusive roosts in the final stages of anticoagulant poisoning, exposure of non-target wildlife to this compound may be more extensive. Most of the birds and mammals exposed to brodifacoum were recovered from areas adjacent to urban development in Santa Clara, Los Angeles, Ventura, Orange, San Benito, Alameda, and Contra Costa Counties.

In February 2000, DPR and DFG staff met with representatives of the Rodenticide Registrant Task Force (RRTF) to discuss the reevaluation of brodifacoum. In addition, individual registrants and the RRTF have submitted data and information. DPR and DFG are drafting a letter that will require brodifacoum registrants to identify mitigation measures to curtail non-target wildlife exposure to brodifacoum.


Pesticide applicators commonly use chlorpyrifos to control insect pests in and around the home. On May 17, 1985, the Department of Health Services (DHS) submitted a study entitled An Assessment of the Hazard from Pesticide Absorption from Surfaces. DHS's assessment addresses the home-use of pesticides. DHS found that use of the products might pose an acute hazard due to inhalation, dermal absorption, or ingestion exposure. At the request of DHS, DPR placed products containing chlorpyrifos for general home use into reevaluation on June 27, 1985.

In 1987, in response to the reevaluation, the basic manufacturer of chlorpyrifos submitted the results of indoor exposure studies. The studies were reviewed and did not raise immediate concerns. In May 1998, DPR informed registrants that it was initiating the risk assessment process for all pesticide products containing the active ingredient chlorpyrifos, including those used in and around the home. On January 20, 2000, DPR issued a notice to registrants identifying the definitive toxicity and exposure studies, and critical endpoints/no effect levels being used in the chlorpyrifos risk assessment. DPR expects to complete its risk assessment of chlorpyrifos in the first quarter of 2001.

In a separate action, U.S. EPA announced on June 8, 2000 that it reached an agreement with the manufacturers of chlorpyrifos to eliminate its use for nearly all household purposes. Under the agreement, registrants will no longer sell pesticide products containing chlorpyrifos for indoor residential use after February 1, 2001. Retail sales of these products will be prohibited after December 31, 2001. Based on this agreement, DPR concluded its reevaluation of chlorpyrifos on August 18, 2000.

CYFLUTHRIN - 52 Products

The pesticide active ingredient cyfluthrin is a non-systemic pyrethroid insecticide registered for use on numerous field, fruit, and vegetable crops, including citrus. In addition, DPR registers pesticide products containing cyfluthrin for use on lawns and ornamental plants, animals, and around industrial, institutional, agricultural, and household structures.

DPR initiated the reevaluation on May 8, 1998, based on its investigation of a May 1997 outbreak of respiratory irritation reported among orange harvesters exposed to residues of cyfluthrin in Tulare County and other pesticide illness reports related to cyfluthrin. As a part of the investigation of the Tulare County incident, DPR's Worker Health and Safety Branch conducted two separate inhalation-monitoring studies in orange groves during orange harvest. DPR determined that, since dust and pollen are a part of the normal working environment, something different in the work environment led to the worker's respiratory irritation symptoms. DPR believes that the application of cyfluthrin to the citrus groves close to harvest led to the respiratory symptoms experienced. DPR compiled the results of its monitoring study in "Health and Safety Report, HS - 1765."

As a part of the reevaluation, DPR required cyfluthrin registrants to submit the results of an inhalation irritation threshold study. In mid-September 1998, the basic manufacturer of cyfluthrin submitted the results of several studies and journal articles concerning the respiratory irritation of cyfluthrin. On October 29, 1998, DPR met with the basic manufacturer to discuss the cyfluthrin reevaluation. At that meeting, DPR agreed to review the submitted studies and journal articles before deciding whether to require additional data. DPR toxicologists are currently determining what types of data are needed to evaluate exposure hazards.

DIPHACINONE - 2 Products

DPR registers products containing the active ingredient diphacinone for use in and around homes, agricultural, and industrial buildings, and in sewers to control rats and mice. DPR currently registers 51 products containing diphacinone. Of the currently registered products, 49 are intended for end use and contain 0.2 percent or less diphacinone. Containing one percent and two percent diphacinone, the two remaining products are concentrates intended for use in the formulation of end-use rodenticides.

DPR initiated a reevaluation of products containing one percent or more diphacinone based on its review of acute toxicity data submitted to support the registration of a one-percent diphacinone product. DPR found the submitted acute dermal toxicity and primary dermal irritation studies to be unacceptable. Without acceptable acute toxicity studies, DPR was unable to determine whether the precautionary statement currently on the label of the one-percent product adequately identifies acute toxicity hazards. After a search of the database, DPR determined that no acute toxicity studies were on file to support the registration of the two-percent diphacinone product. Without the results of acceptable acute toxicity studies, DPR cannot determine whether the precautionary statement currently on the two-percent product label adequately identifies acute toxicity hazards.

Pursuant to the reevaluation, the two registrants submitted several acute toxicity studies. DPR reviewed the data submitted to support the one-percent diphacinone product and determined that an acceptable rabbit acute dermal toxicity study was still needed. In July 1999, the registrant submitted the results of a new acute dermal toxicity study. DPR found the data to be acceptable and on December 27, 1999, accepted an amended label for the one-percent diphacinone product.

After reviewing the data submitted to support the two-percent diphacinone product, DPR determined that an acceptable rabbit acute dermal toxicity study and a dermal irritation study were still needed. In August 1999, the registrant submitted the result of two new studies. DPR found the data to be acceptable and approved an amended label for the two-percent product in June 2000. On July 17, 2000, DPR concluded its reevaluation of diphacinone.

PROPETAMPHOS (Safrotin) - 1 Product

DPR placed products containing propetamphos into reevaluation on March 22, 1990. Applicators use propetamphos indoors as an insecticide. DPR initiated the reevaluation based upon illnesses attributed to use of products containing propetamphos. In addition to the reports of illnesses, DPR was also concerned about the potential for overexposure of humans in contact with rooms treated with propetamphos.

In September 1990, DPR required the registrant to submit (1) a dermal sensitization study, (2) an odor threshold study, (3) an indoor exposure study, and (4) a dermal absorption study. The registrant submitted the dermal sensitization study in January 1991. Rather than conduct an odor threshold study, the registrant conducted a sensory irritation study. The registrant submitted the results of the sensory irritation study in June 1993. The results of an indoor exposure study were submitted in April 1994. Rather than conduct a dermal absorption study, the registrant requested DPR use an assumption of 100 percent dermal absorption.

In February 1998, DPR informed registrants that it was initiating the risk assessment process for pesticide products containing the active ingredient propetamphos. In July 1998, DPR issued a notice identifying the definitive toxicity and exposure studies, critical endpoints/no effect levels used in the propetamphos risk assessment. In November 1999, DPR completed its risk assessment of propetamphos. At the completion of the risk assessment, only one product containing propetamphos remained registered for use in California. Using current toxicity and exposure data, DPR determined that the calculated margins of safety for propetamphos are less than values conventionally considered to be protective of human health. In a notice dated December 27, 1999, DPR informed the registrant that it must institute mitigation measures to reduce exposure from: (1) broadcast applications, (2) gallery (termite) applications, and (3) spot and crack-and-crevice applications made by structural operators. The registrant has agreed to amend their product label to reflect mitigation measures for each of these application types. Because U.S. EPA must approve any amendments to the label of a pesticide product before DPR can accept the amended label, the registrant requested that DPR wait until U.S. EPA completes its reregistration of propetamphos.

U.S. EPA expects to issue their propetamphos Reregistration Eligibility Document (RED) in January 2001. U.S. EPA's RED will require that the registrant amend the label of their product to add the mitigation measures that DPR is requesting.


DPR conducts preliminary investigations on products for which DPR or other state or county agencies have identified possible hazards. As a result of evaluation, the investigations may lead to formal reevaluation.


Blue Chip Germicidal Cleaner is labeled for use in hospitals to clean hard surfaces such as floors, walls, woodwork, and equipment. In compliance with FAC section 12825.5, the registrant of Blue Chip Germicidal Cleaner submitted an adverse effect disclosure. The registrant submitted the results of an eye irritation and an inhalation study.

The data indicate that the product is Toxicity Category II for acute inhalation hazard and Toxicity Category I for eye irritation. The product label does not adequately identify either toxicity hazard. U.S. EPA must approve amendments to pesticide product labels before they can be accepted by DPR. Therefore, the registrant submitted an amended label to U.S. EPA. In September 1999, U.S. EPA required the registrant to make numerous additional changes to this product label. In December 1999, the registrant resubmitted an amended label to
U.S. EPA. The label is still under federal review.

MALATHION - 3 Products

In reviewing the acute toxicity database for products containing malathion, DPR's Medical Toxicology Branch determined that three malathion products might not bear an appropriate signal word and precautionary statement. Data on file with DPR indicate products containing 57 percent malathion are toxicity Category II for acute dermal toxicity and primary eye irritation. DPR considered placing the products into reevaluation. However, the only way for registrants to resolve DPR's concerns would be to amend the labels of their products. Since U.S. EPA must approve all label amendments prior to their acceptance by DPR, we informed U.S. EPA of our concerns. Initially, U.S. EPA expressed reluctance to amend the labels of individual malathion products and wanted to wait until all malathion products finished the reregistration process.

However, in June 1999 U.S. EPA stated that, if the registrants of the malathion products voluntarily amended their product labels to change the signal word and precautionary statement, U.S. EPA would accept the amended labels. DPR informed the two registrants of our concerns regarding acute dermal toxicity and primary eye irritation. One of the registrants agreed to conduct new acute toxicity studies. The registrant submitted the results of the studies to DPR in June 2000 and DPR has not yet reviewed those studies. The second registrant intends to submit an amended label to DPR in January 2001.

For more information, please contact Ms. Ann Prichard, Senior Environmental Research Specialist in the Pesticide Registration Branch, by e-mail at <> or by telephone at (916) 324-3931.

original signed by Barry Cortez

February 28, 2001

Barry Cortez, Chief
Pesticide Registration Branch
(916) 445-4377


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