The other four

Coolant, and ethylene glycol

Updated October 2026

On this page8

The packaging rule The labeling rule A ready-to-use coolant is well over the line Propylene glycol is a different substance Child resistance here has to survive the fluid And special packaging shall not be reused Bittering agents are a separate matter References

Two rules fire at the same number, one about the cap and one about the words.

The packaging rule

Household substances in liquid form containing 10 percent or more by weight of ethylene glycol, packaged on or after June 1, 1974, except articles exempted by 16 CFR 1500.83, shall be packaged in accordance with 1700.15(a) and (b). That means tested child-resistant packaging.

The labeling rule

Because such products are commonly marketed, stored and used in a manner increasing the possibility of accidental ingestion, products at 10 percent or more ethylene glycol shall be labeled with the signal word "warning" and the statement "Harmful or fatal if swallowed".

A ready-to-use coolant is well over the line

Concentrate is mostly glycol and a 50/50 premix is around half, so both are far above 10 percent. The threshold only becomes an interesting question for a product built mainly on propylene glycol or on water.

Propylene glycol is a different substance

The paragraph names ethylene glycol. A formulation built on propylene glycol is answering a different question, and whether it is caught by anything else is a check to run rather than an assumption to carry over.

Child resistance here has to survive the fluid

1700.15(a) requires the special packaging to keep performing in actual contact with the substance and across the openings and closings customary for the size. A gallon jug gets opened repeatedly over a season.

And special packaging shall not be reused

1700.15(c) says so directly, which sits awkwardly beside the appeal of a refillable jug. Decide which paragraph you are under before the marketing is written.

Bittering agents are a separate matter

Many states require a bitterant in antifreeze and engine coolant, and those are state programs with their own concentrations and exemptions. That is a jurisdiction-by-jurisdiction check and it is outside the federal rules this page quotes.

References

16 CFR 1700.14, Substances requiring special packaging. Paragraph (a)(8) covers methanol at 4 percent or more by weight; (a)(11) ethylene glycol at 10 percent or more; (a)(31) nonemulsion liquid household chemical products at 10 percent or more hydrocarbons by weight under 100 SUS at 100 F. law.cornell.edu

16 CFR 1500.14, Products requiring special labeling. Paragraph (b)(2) requires "warning" and "Harmful or fatal if swallowed" for 10 percent or more ethylene glycol; (b)(3)(ii) requires "danger", "Harmful or fatal if swallowed" and "Call physician immediately" for 10 percent or more petroleum distillates, because they may be aspirated into the lungs. law.cornell.edu

16 CFR 1700.15, Poison prevention packaging standards: the packaging must keep performing in actual contact with the substance, effectiveness is not less than 85 percent without a demonstration and 80 percent after one, and special packaging under those paragraphs shall not be reused. law.cornell.edu

Written from federal regulation and from measured catalog data, not from a blending bench. We sell containers and closures; whether a particular closure satisfies a particular clause is a question about that closure and its supplier’s testing, and nothing here certifies a package as compliant. Anything on these pages is a starting point.