Methacrylic acid, and the pen

The requirement

Liquid household products containing more than 5 percent methacrylic acid, weight to volume, in a single retail package shall be packaged in accordance with 1700.15(a), (b) and (c). So above that figure you need tested child-resistant packaging.

Where it bites in this trade

Nail primers and artificial nail liquids are the products the paragraph was written for. A small bottle of primer is exactly the shape of product the rule has in mind.

The exemption, in full

Products applied by an absorbent material contained inside a dispenser, such as a pen-like marker, are exempt provided that the methacrylic acid is contained by the absorbent material so that no free liquid is within the device, and that under any reasonably foreseeable conditions of use it will emerge only through the tip.

Two conditions, both about construction

No free liquid inside, and emergence only through the tip under any reasonably foreseeable use. Neither is a claim you make; both are properties of the device, and the second includes misuse.

So the format is the compliance strategy

Choosing a pen applicator is not a convenience decision here, it is the route out of a tested-packaging requirement. Nowhere else in this library does the shape of the dispenser decide whether a rule applies.

Weight to volume is the stated basis

Which is not the same as weight for weight, and converting between them needs the density. A figure computed on the wrong basis can put you on the wrong side of 5 percent without anybody making an error of judgment.

And a pen still has to hold the liquid

The exemption rests on no free liquid being present. A pen that leaks, floods or weeps at the tip has stopped satisfying the condition the exemption was granted on, which makes the device quality part of the compliance position.

References