D.C. Mun. Regs. tit. 20, r. 20-2505
A warning notice; field notice; directive letter; stop sale, use, or removal order; or a notice of violation shall identify the alleged violation or threatened violation and may require the respondent to conduct monitoring or testing, or to take any responsive or corrective measures the District Department of the Environment (Department) determines reasonable and necessary.
A warning notice; field notice; directive letter; stop sale, use, or removal order; or a notice of violation shall make clear the basis for the notice and that the respondent's failure to take the measures directed will constitute an additional violation of the pertinent statute or regulation.
The Department shall serve a warning notice; field notice; directive letter; stop sale, use, or removal order; or a notice of violation on the respondent or the respondent's authorized representative in person or in a manner likely to insure receipt, including first class mail, fax with return receipt, email with return read receipt, or hand-delivery with certification of service.
After receipt of a stop sale, use, or removal order issued by the Department, no person shall sell, use, or remove the pesticide or device described in the order, except in accordance with the provisions of the order.
When any pesticide, pesticide application, or pest control activity poses a threat to public health, safety, welfare, or the environment, and the responsible person, or the address of the responsible person, is unknown or cannot be located, the Department may serve written notice by conspicuously posting the notice on the property where the threat exists and sending a copy to the owner of the property at the owner's last known address.
D.C. Mun. Regs. tit. 20, r. 20-2505