The safety of chlorpyrifos has been in question for almost three decades. The next step is an outright ban by the EPA, though it's unclear if that will happen.
Large companies can influence Congress, and some fear that the fewer companies there are in a given sector, the more likely they are to get their way.
Supporters and opponents of several proposed mergers among agricultural seed and chemical companies are making their case to lawmakers in Washington.
Beekeepers are pushing the EPA to consider impact on pollinators when reviewing new pesticides.