A thinner bag can be the stronger bag. Ask for the proof.

Our position: less plastic for the same strength is good for everybody. Less plastic for less strength is just a worse bag. The thickness printed on the box will not tell you which one you bought.

Polyethylene resin is a commodity quoted in cents per pound, and the price moves. In winter 2021, a freeze in Texas took a large part of petrochemical capacity offline. The Federal Reserve Bank of Dallas reported high density polyethylene at up to 75 cents a pound in March 2021, a 61 percent jump. A box of bags is sold by count. What a plant controls is the grams in each bag.

Thinner does not have to mean weaker, and the reason is the resin. In the late 1970s, the industry scaled up linear low density polyethylene, a resin as tough as conventional low density polyethylene or tougher, as Plastics Technology wrote in 2005. Blown film was its fastest growing market, with trash bags in the lead in the United States. From the plant floor, the difference is plain. At the same thickness, one film stretches when poked and another pops.

Strength has its own test. In the dart test (ASTM D1709), a weighted dart falls on the film from a fixed height, and the weight is varied until half the samples fail. That result says more about a bag than its thickness does. A mil is one thousandth of an inch, or 25.4 micrometers. Two bags with the same mil count and different resins can behave in opposite ways. Thick does not mean strong, and thin does not mean weak.

The label, at least, can be checked. In the United States, as the rules stood in the fall of 2026, the federal rule (16 CFR 500.16) has bags declared by count, then by dimensions. The model rule that weights and measures inspectors work from, NIST Handbook 130 (2024 edition), adds thickness, in micrometers and mils, and capacity for lawn and trash bags sold at retail. NIST Handbook 133 (2026 edition) gives inspectors the arithmetic: length times width, times two for both sides, times thickness, times density, times count. The result is the weight the box should have. A lighter box points to bags thinner than the label says.

In Canada, on the same date, the Consumer Packaging and Labelling Act requires the net quantity on the principal display surface, in English and in French. For a product sold by count, the regulations tolerate no missing article when the declared count is under 50. Zero.

What this changes for you. If you buy bags or film, stop reading the mil count as a grade. Ask for two things in writing: the declared thickness, and the dart test result with its method. Then weigh a box. The scale checks the first answer. A full bag of trash checks the second.