Pesticide manufacturers are pushing back against pressure to disclose all of the chemicals in pesticide formulations, Chemical & Engineering News reports.

Of particular concern to regulators and those calling for mandatory labeling are the inert ingredients in pesticides that perform functions other than controlling pests.

Examples of these are emulsifiers, solvents, aerosols, fragrances, dyes, and other chemicals. Many companies say this information is proprietary.

In October the EPA proposed removing 72 chemicals from its list of substances approved for use as inert ingredients in pesticide products.