S. 1999 amends federal pesticide law to require the Environmental Protection Agency (EPA) to coordinate with the U.S. Department of Agriculture (USDA) when making decisions about pesticide safety measures and regulations. Specifically, the bill mandates that whenever the EPA requires risk mitigation measures for a registered pesticide, it must work with the USDA and publish an economic analysis showing how those measures will affect farmers and other users. The legislation also requires the EPA to consult with the USDA before making decisions on pesticide registrations or food residue standards, ensuring that agricultural data and information about alternative pesticides are considered. Additionally, the bill calls for coordination with the departments of Interior and Commerce regarding pesticide impacts on endangered species, with all agencies considering the risks and benefits to farmers. The coordination requirements can be waived if the EPA, USDA, and pesticide manufacturers agree, provided the agreement is publicly documented.