By Carey Gillam

(Reuters) - Three environmental and public health groups sued the Environmental Protection Agency on Wednesday, seeking to press it to move forward with rules that would require public disclosure of certain pesticide ingredients.

The Center for Environmental Health, Beyond Pesticides, and Physicians for Social Responsibility, all non-profit advocacy groups, filed the lawsuit in U.S. District Court in San Francisco.

The groups claimed there has been an "unreasonable delay" on the EPA's part in finalizing rules to require chemical manufacturers to disclose hazardous inert ingredients in their pesticide products.

The groups said there are more than 350 inert pesticide ingredients that can be just as hazardous as active ingredients that are labeled and can comprise up to 99 percent of a pesticide's formulation. Of the common inert ingredients, many are classified as carcinogenic, possibly carcinogenic or potentially toxic, the lawsuit said.

More than 20 public health groups and a coalition of state attorneys general petitioned EPA in 2006 to take action on this issue. EPA said in 2009 that it was starting the rule-making process regarding disclosures of such ingredients.

But the lawsuit claimed that since 2009 EPA has taken no further action to adopt any new rules on disclosure of inert ingredients.

"EPA's unreasonable delay continues to leave the public uninformed and unable to protect themselves from the hazardous chemicals they are being exposed to through the use of pesticide products," the lawsuit said.

EPA officials did not immediately respond to requests for comment.

In a 2009 letter to the groups, EPA said that it intended to "effect a sea change in how inert ingredient information is made available to the public." But it also said it was not committing to any particular outcome.

(Reporting by Carey Gillam in Kansas City; Editing by Jonathan Oatis)