EPA Closes Registration Review for 19 Discontinued Pesticide Active Ingredients
18 September 2026, Washington, D.C.: The US Environmental Protection Agency has formally closed registration review cases for 19 pesticide active ingredients, ranging from older organophosphate insecticides to niche biological control agents, after determining that every product associated with each case has already been cancelled. The notice, published in the Federal Register on September 17, 2026, does not introduce new restrictions. Instead, it removes these chemistries from the EPA’s active regulatory review docket because there is nothing left on the market for the agency to review.
The closures fall under Section 3(g) of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), which requires EPA to reevaluate every registered pesticide active ingredient on a 15-year cycle to confirm it still meets current safety standards. When every product containing a given active ingredient has voluntarily or involuntarily left the market, EPA closes the case rather than continuing to run it through the review pipeline, freeing agency resources for chemistries that are still in active commercial use.
The notice covers a mix of legacy synthetic pesticides and older biological or semiochemical products, several of which have not been sold for years. Two entries, methyl-parathion and fenitrothion, are older organophosphate insecticides that were phased out amid tightening restrictions on organophosphate chemistry over the past two decades. Methiocarb, a carbamate insecticide and bird repellent, and dicloran (DCNA), a fungicide once used on stored fruit and vegetables, are among the other synthetic chemistries closed out. The list also includes several biological and pheromone-based products, among them a killed Streptomyces acidiscabies strain, two fungal biocontrol agents (Lagenidium giganteum and Phoma macrostoma), and the olive fly sex pheromone, reflecting how even niche biopesticide registrations eventually cycle out of the market and off EPA’s books.
Below is the full list of active ingredients closed in this notice, with their EPA case numbers as published in the Federal Register:
| # | Active Ingredient | EPA Case Number |
|---|---|---|
| 1 | Alpha-Chlorohydrin | 4120 |
| 2 | Citral | 6314 |
| 3 | Delta-Dodecalactone | 6354 |
| 4 | Dicloran (DCNA) | 0113 |
| 5 | 1,7-dioxaspiro[5.5]undecane (Olive Fly Sex Pheromone) | 6369 |
| 6 | Fenitrothion | 0445 |
| 7 | Ferbam | 8000 |
| 8 | Imazamethabenz | 7207 |
| 9 | Killed Streptomyces acidiscabies strain RL-110T | 6523 |
| 10 | Lagenidium giganteum | 6068 |
| 11 | L-Carvone | 6306 |
| 12 | Methiocarb | 0577 |
| 13 | Methyl-parathion | 0153 |
| 14 | Muscodor albus strain SA-13 | 6303 |
| 15 | Neodecanamide, N-methyl | 7428 |
| 16 | Phoma macrostoma strain 94-44B | 6524 |
| 17 | 4-tertiary-Amylphenol and Salts (PTAP) | 3016 |
| 18 | Trimedlure | 6045 |
| 19 | Typhula phacorrhiza strain #94671 | 6546 |
For each active ingredient, the Federal Register notice identifies an individual EPA Chemical Review Manager responsible for that case, with contact information provided so registrants, growers, or other stakeholders can direct questions to the appropriate reviewer. The underlying docket is EPA-HQ-OPP-2017-0751.
This kind of administrative closure happens periodically as EPA works through its FIFRA registration review backlog, and it is largely a bookkeeping exercise rather than a market-moving event. None of the 19 active ingredients closed in this batch have significant remaining commercial volume in the United States, so growers and formulators are unlikely to see any practical impact from the closures themselves.
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