Pesticide Sensitive Registry
The pesticide sensitive registry is for people who have or can obtain documentation of sensitivity to pesticide products from a licensed Colorado physician.
To be placed on the registry, a certificate must be signed by a physician licensed to practice medicine in the state of Colorado, stating that you have a medical condition that makes you sensitive to pesticides.
The registry does not prevent an application of pesticides but only requires that commercial applicators (like lawn care companies) make at least two attempts to notify people on the registry at least 24 hours before an application is made to an abutting property (property that touches yours) so that you can leave for a period of time or make other preparations. If notification attempts are unsuccessful, the applicator must make a final attempt immediately prior to the application and place a notice on your door.
The law that outlines the requirements of the Pesticide Sensitive Registry can be found under 35-10-112 of the Pesticide Applicators' Act and in Part 12 of its associated Rules.
Mosquito and Other Public Health Pesticide Applications
Mosquito spraying is a "public health pest control" application performed by city, county or other local authorities or by companies they hire under their local authority to protect the health of the people in the community. The notification requirements of the Pesticide Sensitive Registry do not apply to mosquito or other public health or wide-scale pest control applications.
The pesticide registry maintained by the Colorado Department of Agriculture only requires notification of pesticide sensitive persons for pesticide applications made to control pests of lawns, ornamental trees and shrubs, wood destroying organisms such as termites, and residential, commercial, and interior plant pests.
Any notification provided to the public during a public health pest control operation by municipalities and/or commercial applicators is done as a courtesy to those requesting, not because it is a state law requirement.
If you don't want your property included in the spraying, you must contact the entity conducting these applications and ask them to exclude your property from the program, if they are able to do that.
If you have questions regarding the date, time, or area of an upcoming public health pest control application (i.e. mosquito control) you should contact your local health department or pest district in charge of such applications.