10.4 Pesticide Waste, Rinsate & Excess Product Disposal

10.4 Pesticide Waste, Rinsate & Excess Product Disposal

Section 8.3 covered what happens to the empty container — triple rinsing or pressure rinsing, puncturing, and recycling or landfill. This section covers everything else that leaves the operation without being applied as originally planned: leftover tank mix, rinse water, product that has gone bad, product whose registration has been cancelled, and the contaminated materials generated by a spill or a cleanup.

The governing New Mexico provision is NMSA 1978, Section 76-4-30 ("Discarding and storing of pesticides and pesticide containers"), which makes it unlawful to discard, transport, or distribute pesticides or their containers "in a manner that may cause injury to humans, vegetation, crops, livestock, wildlife or beneficial insects or pollute any waterway." Every rule below is an application of that sentence.

---

The Disposal Hierarchy

   BEST   ┌────────────────────────────────────────────────────────┐
     ▲    │ 1. DON'T CREATE IT — buy and mix only what you'll use  │
     │    ├────────────────────────────────────────────────────────┤
     │    │ 2. USE IT — apply per the label at a labeled site      │
     │    ├────────────────────────────────────────────────────────┤
     │    │ 3. RECYCLE IT — rinsate as make-up water; container    │
     │    │    recycling through an approved program               │
     │    ├────────────────────────────────────────────────────────┤
     ▼    │ 4. DISPOSE OF IT — hazardous waste contractor or an    │
   WORST  │    agency collection program. Slowest and costliest.   │
          └────────────────────────────────────────────────────────┘

Every step down this ladder costs more money, more paperwork, and more risk. The practical implication is that disposal management begins at the purchase order and the mixing calculation, not at the end of the season.

---

Step 1: Do Not Create the Waste

• Buy only what the season's plan supports (Section 10.2).
• Calculate the mix accurately. Section 8.2 gave the tools: measure the area, verify ground speed, calibrate the sprayer, and compute the tank volume the job actually needs. Mixing a full tank for a three-quarter-tank job creates the problem this section exists to solve.
• Mix the last load short deliberately, so that the final tank runs out on the field rather than returning to the yard partly full.
• Order in container sizes that match the job. A 2.5-gallon jug that fits the job beats a 30-gallon drum that leaves 22 gallons aging in the shed.

---

Step 2: Use Leftover Tank Mix Lawfully

A partly full tank of finished spray is not waste as long as it can be applied lawfully.

The rule: apply it to a site listed on the label, at or below the labeled rate, and within all label restrictions.

That single sentence carries four constraints worth spelling out:

1. Labeled site only. Spraying the leftover on a turn row, a fence line, or a shop yard that the label does not list is an application to an unlisted site — the classic FIFRA Section 12(a)(2)(G) violation from Section 2.1.
2. At or below the labeled rate. Dumping a half tank on a small area to empty it quickly exceeds the maximum labeled rate and is misuse. FIFRA Section 2(ee)(1) permits applying below the labeled rate unless the labeling prohibits it, so spreading the leftover thin across additional labeled acreage is the lawful move.
3. Within the maximum seasonal rate. Check that the extra pass does not push the site over the label's maximum cumulative rate per season.
4. Within every other restriction — pre-harvest interval, restricted-entry interval, buffer, pollinator, and endangered species restrictions all still apply.

Never:

• pour leftover mix on the ground, in a ditch, an arroyo, an acequia, or a road shoulder;
• pour it into a storm drain, a sanitary sewer, or a septic system — a septic system's bacteria are killed by pesticides and a sanitary sewer passes the product to a treatment plant that cannot handle it;
• bury it;
• burn it.

---

Step 3: Manage Rinsate as a Resource

Rinsate is the dilute pesticide solution produced by rinsing tanks, hoses, booms, and empty containers. It is the most common pesticide waste an operation generates, and it is also the easiest to eliminate.

Two cautions govern rinsate reuse:

• Compatibility and crop safety. Rinsate containing a herbicide must not become make-up water for an insecticide going onto a sensitive crop. This is the same contamination logic that drives herbicide segregation in storage (Section 10.2), and the consequence is the same: crop injury discovered in the field weeks later.
• Rate accounting. Rinsate carries active ingredient. Using it as make-up water adds that active ingredient to the next load, and the combined rate must still respect the label maximum.

Where the wash pad matters. Section 6.2 established New Mexico's shallow valley water tables and coarse, low-organic soils. Rinsing a sprayer on bare ground beside an irrigation lateral delivers dilute pesticide straight toward the water table. A designed, curbed, impermeable wash and containment pad that drains to a rinsate collection sump is the single best capital investment a New Mexico commercial applicator can make for both compliance and groundwater protection.

---

Step 4: Dispose of Unusable Product Properly

Some product genuinely cannot be applied: the registration has been cancelled, the label has become unreadable, the formulation has frozen and separated, the material has caked beyond re-suspension, or the crop it was bought for is gone.

This material is not ordinary trash, and the decision must not be improvised.

Absolutely prohibited routes: pouring down any drain, sewer, or septic system; discharging to a ditch, acequia, arroyo, or any waterway; burying on site; open burning; and placing in ordinary refuse. Each of these is squarely within the conduct NMSA 1978, Section 76-4-30 forbids, and each is independently a label violation because the Storage and Disposal box on essentially every label prohibits it.

---

Contaminated Materials from Spills and Cleanups

Everything Section 10.3 generated is pesticide waste and follows the Step 4 routes:

• used absorbent (cat litter, vermiculite, sorbent pads);
• scraped contaminated soil;
• disposable coveralls, gloves, and boot covers worn in concentrate;
• brooms, dustpans, and rags used in the cleanup;
• the salvage drum and any leaking container it contains.

Heavily contaminated PPE is discarded, not laundered. Section 5.1 covers the laundering rules for routinely used PPE; clothing soaked in concentrate is past that threshold.

---

Records

Keep disposal documentation with the application records:

1. What was disposed of — product, EPA registration number, formulation, and quantity.
2. Why it was unusable.
3. Which route was used, and the contractor's manifest or the collection program receipt.
4. The date and the person responsible.

Section 1.3's two-year retention under 21.17.50.10 NMAC is the baseline for application records; disposal manifests are worth keeping longer, because they are the proof that a drum which left your yard was handled lawfully.

Exam Framing: the highest-yield answers in this section are that leftover tank mix goes on a labeled site at or below the labeled rate, that rinsate becomes make-up water for the next compatible load, and that unusable product goes to a hazardous waste contractor or a collection program rather than any drain, ditch, burial pit, burn barrel, or dumpster.