Department of Pesticide Regulation Logo

Paul E. Helliker Director

Department of Pesticide Regulation

  California Notice 2000-3

California State Seal
Gray Davis

Winston H. Hickox
Secretary, California
Protection Agency

July 1, 1999 THROUGH December 31, 1999

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 adopts regulations 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 - 34 Products

Brodifacoum is registered in California to control Norway rats, roof rats, and house 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.

During the course of the reevaluation, DPR and DFG plan to identify the pathways that result in wildlife exposure to brodifacoum and curtail exposure through effective mitigation measures.


Applicators use copper naphthenate as a fungicide and wood preservative to protect wood from fungal decay and insect attack. DPR placed products containing copper naphthenate into reevaluation on December 28, 1995, based upon concerns regarding use of the products indoors. DPR's Worker Health and Safety Branch received a number of reports of illnesses following exposure to the indoor use of pesticide products containing copper naphthenate. The illnesses appear to be associated with inhalation exposure resulting in nausea, dizziness, and headaches. In some cases, the structure could not be occupied for an extended period of time following treatment.

In February 1996, DPR discussed its concerns regarding copper naphthenate with the U.S. Environmental Protection Agency (U.S. EPA). Based upon DPR's information, U.S. EPA decided that indoor use of copper naphthenate was of national concern and, therefore, best addressed by U.S. EPA. U.S. EPA met with representatives of the Naphthenate Salts Research Task Force (Task Force) to discuss this issue. In October 1996, the Task Force sent U.S. EPA a mitigation proposal. U.S. EPA responded to the Task Force's proposal in December 1996, after consultation with DPR. U.S. EPA and DPR found certain elements of the proposal to be acceptable; however, the proposal needed further modification.

In January 1997, U.S. EPA received a letter stating that the Task Force would not be supporting continued indoor use of copper naphthenate. In March 1997, the Task Force submitted amended labels to both U.S. EPA and DPR for products registered to the three basic manufacturers of copper naphthenate. The manufacturers revised the labels of their products to delete all indoor uses and to add the statement "For Exterior Use Only." In addition, a statement has been added requiring the use of respirators during prolonged or frequent use of the product. Task Force members also added a toll free number and the statement, "In case of medical questions, emergencies, or accidents involving this product, call 1-800-XXX-XXXX," to the labels of their products. DPR reviewed the amended labels and sent comments to U.S. EPA.

Registrants have amended the labels of 25 of the 27 currently registered copper naphthenate products to comply with U.S. EPA and DPR requirements. The registrant of the remaining two copper naphthenate products intends to withdraw the registrations of the products for 2000. Once the registrations of the products have been withdrawn, DPR plans to conclude the reevaluation of copper naphthenate

CYFLUTHRIN - 39 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 feels 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. After reviewing the data, DPR determined that, although limited in scope, the data could be used to generate a no-effect level for risk assessment. The study was limited by the constraints of the Human Subjects Committee. The Human Subjects Committee would not permit a double-blind study to be carried out on human subjects.

In May 1999, the Agricultural Reentry Task Force commenced a study to assess exposure to workers from cyfluthrin residues in a treated orange orchard. The study monitored air levels and observed the levels of dermal exposure to workers harvesting oranges. DPR expects preliminary results of the study to be available in the first quarter of 2000.

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 Norway rats, roof rats, and house 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 recently 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 product adequately identifies acute toxicity hazards. After a search of the database, DPR determined that no acute toxicity studies are on file to support the registration of a two percent diphacinone product. Without the results of acceptable acute toxicity studies, DPR cannot determine whether the precautionary statement currently on the product label adequately identifies acute toxicity hazards.

In the fall of 1998, 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. On December 27, 1999, DPR accepted an amended label for this 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 a new acute dermal toxicity study and a dermal irritation study. In November 1999, the registrant submitted an amended label for the product. DPR is currently reviewing the amended label.

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 penetration 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 was considering feasible mitigation measures that would reduce exposure to the following types of residential, institutional, and industrial uses of propetamphos: (1) broadcast applications, (2) gallery (termite) applications, and (3) spot and crack-and-crevice applications made by structural operators. The notice gives the registrant 60 days to submit proposed mitigation measures.


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. In January 2000, DPR plans to issue 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 second quarter of 2000.


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 Food and Agricultural Code (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 his product label. In December 1999, the registrant resubmitted an amended label to U.S. EPA.

CLETHODIM - 4 Products

The active ingredient clethodim is used as a systemic postemergence herbicide to control annual and perennial grasses in broadleaf crops. In compliance with FAC section 12825.5, the basic manufacturer of the pesticide active ingredient clethodim submitted an adverse effects disclosure. DPR reviewed the submitted dermal sensitization study and, based on the results of the study, determined that clethodim is a skin sensitizer. DPR informed the registrant of its review and asked the registrant how he intended to mitigate the dermal sensitization hazard.

At the request of the registrant, DPR agreed to allow the registrant to run another dermal sensitization study. The results of the new dermal sensitization study were submitted and indicated that clethodim is a dermal sensitizer. The registrant has amended the labels of three of its clethodim products to add a dermal sensitization precautionary statement. The registration of the fourth clethodim product was not renewed for 2000. This resolves DPR's concerns with regard to the active ingredient clethodim.

MALATHION - 2 Products

In reviewing the acute toxicity database for products containing malathion, DPR's Medical Toxicology Branch determined that two 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 at amending 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 registrant decided to conduct new acute toxicity studies using his formulated product. The results of the studies will be submitted to DPR in April 2000. The second registrant submitted a proposed amended label to DPR for preliminary review. If the amended label addresses all of DPR's concerns, it will be sent to U.S. EPA for their approval.

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


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


830 K Street - Sacramento, California 95814-3510 -
A Department of the California Environmental Protection Agency