Carbon Monoxide for Burrowing Rodent Control: Regulation and Updated Questions and Answers
The Department of Pesticide Regulation (DPR) adopted Title 3, California Code of Regulations (3 CCR) section 6695 to mitigate hazards from use of carbon monoxide (CO) pest control devices to control burrowing rodent pests. Requirements include: device users are prohibited from using the devices inside structures; users must follow a setback distance from inhabited structures; use is prohibited on burrow openings which may contain non-target animals; and certain employers must follow protective eyewear, recordkeeping, and adverse effect disclosure requirements.
This letter supersedes the Question-Answer portion of ENF letter 15-11 by revising guidance to be consistent with 3 CCR section 6695.
General
Q1. What is a CO pest control device?
A: CO is colorless, odorless, and toxic to humans and animals. A CO pest control device is a method or instrument which uses CO to prevent, eliminate, destroy, or mitigate burrowing rodent pests. These devices generally use an internal combustion engine to force pressurized CO gas through a hose into the rodent burrow system. The pressurized system allows the CO to move farther through the burrow system than it would with other passive application methods, such as gas cartridges.
Q2. Do CO pest control devices need to be registered with DPR? Is there a list or database of CO pest control devices?
A: No. At this time, DPR does not require registration of CO pest control devices. There is no list or database of CO pest control devices available for purchase in California.
Q3. Does the use of a CO device to control burrowing rodents constitute “pest control?”?
A: Yes. Using a device to control pests is a form of pest control under California law.
Q4. What are “rodents” under this regulation?
A: Food and Agricultural Code (FAC) section 12757 defines “rodent” for the purposes of this regulation. “Rodent” includes all members of the order Rodentia (for example, mice, rats, pocket gophers, voles, and ground squirrels) and all rabbits and hares. Section 6695(a)(5) prohibits CO device users from targeting burrowing animals which are not rodents, such as moles, racoons, and skunks. For purposes of this regulation, voles are covered by the term “field mice.”
Q5. What should users look for when purchasing a CO pest control device?
A: Federal law requires a device that is built, then moved, sold, or distributed be labeled with the EPA Establishment Number of the establishment in which the device was manufactured. The EPA Establishment Number is a unique, site-specific number U.S. EPA assigns to each establishment that produces any pesticide, active ingredient, or device. On the device label, the establishment number is preceded by the phrase “EPA Est.”
Q6. Are CO pest control device retailers required to provide information to users on the requirements of 3 CCR section 6695?
A: No. Persons purchasing or using CO pest control devices are responsible for investigating the applicable laws and regulations and complying with them. However, DPR encourages CO pest control device retailers to provide California purchasers information on 3 CCR section 6695 to aid in compliance with the regulation.
Q7. Are there any label requirements for CO pest control devices?
A: Yes. This device must have a permanently affixed warning in plain view of the operator incorporating the specific text contained in FAC section 6025.4(a):
DANGER: Carbon monoxide is a poisonous gas that is odorless and colorless. Exposure to carbon monoxide can kill within minutes. Never use in structures inhabited by humans or livestock. The device must be used in accordance with all existing laws and regulations including Chapter 1.5 (commencing with Section 2050) of Division 3 of, known as the California Endangered Species Act, and Sections 4002 and 4003 of, the Fish and Game Code.
As noted in the response to Question 5, federal law requires that a device that is built, then moved, sold, or distributed be labeled with the U.S. EPA Establishment Number of the establishment in which the device was manufactured. A user may still manufacture their own device; however the user-manufactured device can only be used on the user’s own property. Pest Control Businesses (PCBs) may only manufacture devices if they are an EPA registered establishment.
Device Use
Q8. What licensing or certification is required to use CO pest control devices?
A: Most users of CO devices will not need to be licensed or certified to use these devices. However, a person advertising, soliciting, or operating as a pest control business must be licensed as a PCB by DPR, and follow all other applicable requirements.
Q9. Do the requirements of section 6695 apply to all users of these CO pest control devices?
A: The requirements of subsection (a) apply to all users. The requirements of subsection (b) apply to PCBs and local government agencies, districts, or other political subdivisions of the state. Examples of the latter include, but are not limited to:
- cemetery districts
- city, county, or regional parks or park districts
- other city or county departments, such as public works
- community services or recreation districts
- irrigation, utility, or water agencies or districts
- reclamation and levee maintenance districts
- school districts
- community college districts
- vector control districts or agencies.
Q10. Where can CO pest control devices be used?
A: Consistent with the warning label required by FAC section 6025.4(a)(1), section 6695(a)(2) prohibits use of a CO pest control device in structures that may be inhabited by people or livestock. Further, section 6695(a)(3) restricts how close a user may treat a burrow opening from a structure inhabited by people or livestock (whether occupied or not) based on the type of rodent targeted and typical burrow opening.
With those limitations in mind, these devices can be used in both agricultural and non-agricultural settings to control burrowing rodent pests.
Q11. What constitutes an inhabited structure?
A: There are many examples of structures that humans may be present in or occupy (“inhabit”) which are covered by subsections (a)(2) and (a)(3). These include, but are not limited to, tool sheds, shops, barns, and stables.
Q12. Can users connect tubing from the exhaust pipe of an automobile?
A: DPR does not recommend this. It would be difficult, if not impossible, to maintain compliance with the warning requirement of FAC section 6025.4(a)(1) and requirement for the device to have an EPA Establishment Number consistent with federal law and 3 CCR section 6695(a)(1).
Q13. How would a user learn about the differences between burrowing rodent pests and other non-target vertebrate animals?
A: To protect non-target species and comply with the requirements of 3 CCR sections 6600(b) and 6695(a)(5), users should be able to identify the target pest and understand its biology. Use of these devices should be limited to individuals who are trained to distinguish dens and burrows of target species (rodents, all rabbits and hares) from those of non-target species (mole, racoon, skunk, snake, fox, burrowing owl, etc.).
Individuals can receive training from a variety of sources including wildlife biologists, County Agricultural Commissioner (CAC) staff, University of California Cooperative Extension advisors, state or federal officials, or others. There are also many existing online resources that can be utilized to help CO pest control device users and CAC staff differentiate between burrows of target and non-target species. These include DPR’s Endangered Species Field Identification Cards, CDFA’s Vertebrate Pest Control Handbook, the University of California Statewide IPM Program’s Pest Notes Library, or the University of Nebraska’s Prevention and Control of Wildlife Damage.
After learning about target and non-target species, the CO pest control device user should survey the proposed treatment area for evidence of nontarget animals to determine if any nontarget animals could be harmed by the treatment. Many rodent and wildlife species are easily seen during daylight hours. A good visual inspection involves systematically viewing the area with enough detail and identify all burrow openings (main entrance and all emergency exit holes) and burrows/areas that should be avoided, such as those occupied by nontarget animals including threatened or endangered species. For example, a portable borescope can be used to examine the interior of burrow systems to visually determine if it is occupied or contains any non-target species before a CO treatment.
Proper identification of the rodent, the burrow, and the habitat are also very important when it comes to certain animals that might be legally protected. For assistance in determining if there are threatened or endangered species in the treatment area, please contact DPR’s Endangered Species Project.
Advisories: Fish and Game Code section 2087(a) permits an accidental (defined in the law as unintended or unforeseen) take of a candidate, threatened, or endangered species by a farmer or rancher, or by a contractor (such as a PCB) on a farm or a ranch, during otherwise lawful routine and ongoing agricultural activities. Any accidental take must be reported to the Department of Fish and Wildlife (CDFW) within 10 days.
Use of CO devices in other settings (e.g., parks, schools, colleges, cemeteries, etc.) in an area known to be occupied by an endangered or threatened species (e.g., the San Joaquin Kit Fox which may den in a variety of areas such as rights-of-way, fallow/ruderal habitat, vacant lots, etc., and may switch dens frequently) may require an incidental take permit from CDFW. Users should contact the appropriate CDFW Regional Office for more information.
Q14. What Personal Protective Equipment (PPE) is required?
A: The pressurized CO created by these devices creates a potential for debris to be sent back toward the user. Subsection (b)(1) requires certain employers (see response to Question 9) to ensure their employees wear protective eyewear. While protective eyewear is not required for all users, DPR encourages all users to wear protective eyewear while operating these devices.
Q15. How should CACs respond to CO device complaints or incidents?
A: CAC staff should respond as they would to any other pest control complaint or incident.
Q16. Should CACs conduct use inspections?
A: CAC staff may encounter a CO pest control device in use. In such cases, DPR leaves the decision to conduct a partial inspection to assess compliance with PCB licensing and registration requirements in FAC sections 11701 and 11732, and pest control requirements of 3 CCR sections 6600 and 6695 to CAC discretion.
Recordkeeping
Q17. Is the use of a CO pest control device required to be reported on a Pesticide Use Report?
A: No. Subsection (b)(2) requires certain employers to maintain records. Pesticide use reporting is required only for the use of registered pesticides, not for the use of a device.
Q18. For subsection (b)(2), what does “Length of time the device was operated for every treatment” mean? Does that mean users must record the amount of time per burrow?
A: No. The intent is for users to record the total time they use CO pest control devices at the site, not the individual per burrow time.
Q19. Should CACs conduct headquarter inspections?
A: CAC staff may conduct Pest Control Headquarters and Employee Safety Inspections routinely, or in response to a complaint or incident. Section 6695(b) requires certain employers must maintain limited records of when, where, and for how long the device was used. Many of these employers will already be familiar to the CAC. For headquarter inspections on these employers, ask if the employer has or uses a CO pest control device. If they do, ascertain compliance with subsection 6695(b) and document the findings on the inspection report form.
If you have any additional questions on this regulation, please contact the Enforcement Branch Liaison assigned to your county.
Sincerely,