Alachlor Storage & Tank Compatibility

Storing Alachlor? Start Here

Alachlor (C₁₄H₂₀ClNO₂) is a chloroacetanilide pre-emergent herbicide used to control annual grasses and many broadleaf weeds in corn, soybeans, peanuts and other row crops. In its pure technical form it is an odorless, near-colorless crystalline solid that is essentially insoluble in water. Commercially, however, alachlor is almost never handled as a dry solid: it is dissolved at high loading into an aromatic-solvent (xylene-rich) emulsifiable concentrate that is later diluted with water for field spraying. This is the form that fills agricultural bulk tanks, mix-load stations and tote systems. Material of construction matters because that organic carrier — not the active ingredient — governs container chemistry: aromatic solvents swell and permeate ordinary polyethylene, while the formulation is also a suspected carcinogen and is extremely toxic to aquatic life, so secondary containment integrity is non-negotiable. Choosing a vessel rated for the solvent carrier protects both the product and the surrounding environment.

Can you store alachlor in a poly tank?

Honestly, no — not the commercial product. The technical active ingredient is a neutral solid that, on its own, would not chemically attack polyethylene. But alachlor reaches the field as an emulsifiable concentrate dissolved in xylene and related aromatic solvents, which typically make up more than half the formulation. Aromatic hydrocarbons are one of the well-known weaknesses of HDPE and crosslinked polyethylene: published resistance charts rate xylene, toluene and benzene as "not recommended" for HDPE because the solvent swells, softens and permeates the wall over time, leading to stress cracking and seepage. For bulk storage, transfer or day tanks holding the concentrate, choose stainless steel (304/316), a phenolic- or epoxy-novolac-lined steel tank, a vinyl-ester FRP vessel rated for aromatic service, or a fluoropolymer-lined tank, and use FKM (Viton) seals rather than EPDM. Reserve polyethylene only for the heavily water-diluted field spray solution, and even then verify against the diluted formulation's solvent content.

Material compatibility at a glance

Technical alachlor is a benign neutral solid, but it is sold and stored as an emulsifiable concentrate dissolved in xylene / aromatic solvent, so the tank must resist that solvent. Specify stainless steel, lined steel, solvent-grade FRP or fluoropolymer-lined vessels with FKM seals; polyethylene is not suitable.

Ratings: S suitable · C conditional / limited · U unsuitable. Verify against the cited resistance charts and your concentration/temperature before specifying.

The safety that actually matters

• Suspected carcinogen (H351): Alachlor is classified as suspected of causing cancer; minimize exposure, use closed-transfer systems and respiratory protection where aerosols or vapors are possible.
• Acutely toxic if swallowed (H301/H302): Toxic to harmful by the oral route; never eat, drink or store food near handling areas and wash thoroughly after contact.
• Skin sensitizer and irritant (H317/H316/H335): May cause allergic skin reactions plus skin and respiratory irritation; wear chemical-resistant gloves, eye protection and adequate ventilation.
• Target-organ effects (H371/H373): May damage organs from single or repeated exposure; control chronic low-level exposure with engineering controls and monitoring.
• Severe aquatic hazard (H400/H410): Very toxic to aquatic life with long-lasting effects; provide full secondary containment and prevent any release to soil, storm drains or surface water.
• Aromatic-solvent carrier: The emulsifiable concentrate contains flammable aromatic solvent — keep away from ignition sources, ground and bond during transfer, and treat empty containers as still hazardous.

Common questions

What kind of chemical is alachlor?

It is a chloroacetanilide pre-emergent herbicide (IUPAC: 2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide), used to control grasses and broadleaf weeds in row crops. Pure alachlor is a crystalline solid, but it is sold as a liquid emulsifiable concentrate dissolved in aromatic solvent.

Why is polyethylene not recommended for bulk alachlor?

Because the commercial concentrate is dissolved in xylene-type aromatic solvent. Aromatic hydrocarbons swell and permeate HDPE and XLPE, causing softening and stress cracking. Resistance charts rate xylene and toluene as not recommended for polyethylene, so a solvent-resistant tank is required.

What tank material should I use for alachlor concentrate?

Use stainless steel (304 or 316), a phenolic- or epoxy-novolac-lined steel tank, an aromatic-rated vinyl-ester FRP tank, or a fluoropolymer-lined vessel. Specify FKM (Viton) elastomers for gaskets, diaphragms and hose; avoid EPDM, which the aromatic carrier attacks.

Is alachlor dangerous to the environment?

Yes. It is classified as very toxic to aquatic life with long-lasting effects (H400/H410) and is a suspected carcinogen. Full secondary containment and spill prevention are essential to keep it out of soil, drains and surface water.