The NIST Solves 'The Case of the Aerosol Can'

The National Institute of Standards and Technology (NIST) is the branch of the federal government dedicated to standardizing units of measurement and making sure industries comply with these standards. Everything from the smart electric power grid and electronic health records to atomic clocks, advanced nanomaterials and computer chips, rely in some way on technology, measurement, and standards provided by the National Institute of Standards and Technology.

The NIST also solves disputes related to measurements of all types of products, including those on store shelves, like cereal boxes, pet food cans or aerosol products. Recently the office of weight and measures (OWM), a subsidiary of the NIST, was called to solve a dispute over the way aerosol products are labeled and sold.

The dispute started a few years ago when an inspector in Massachusetts noticed a spray can in a store that, according to the label, was being sold by fluid volume. Under the Uniform Packaging and Labeling Regulation, section 130 of the NIST Handbook, aerosols and similar pressurized containers should be sold by net weight and not by volume of the substance. As it was in violation of section 130, the state officials contacted the manufacturer and inform them about this miss-labeled product.

It can be hard to determine from the exterior of the container (left), but contents may be either mixed with the propellant (center) or confined in a bag (right). (Source: Credit: NIST)When confronted, the company stated that they use "bag-on-valve" (BOV) technology. BOV containers, which can be seen in the right portion of the diagram, are normally used in many consumer products, such as deodorants, window cleaners, sunblock sprays, insecticides and furniture polish.

"A lot of BOV manufacturers do not regard themselves as 'similar,'" says David Sefcik of OWM, because their technology is different in that the active ingredient is contained in a sealed bag inside the can and the needed pressurized propellant gas surrounds the bag, but never leaves the can. In the case of many standard aerosol containers that use a mixture of the active ingredient and a propellant gas, both compounds are expelled at the same time.

"The manufacturer argued that because its products don't expel the propellant, it should continue to use its existing net-volume declaration," Sefcik explained. "The state contacted us. We recommended that net weight be used for BOV products, and encouraged them to bring the issue before the National Conference on Weights and Measures (NCWM), which makes the ultimate decisions about such questions."

Despite a couple years of discussion, industry representatives and trade associations were not able to solve the case of the aerosol can. The main disagreement came from the fact that even federal regulations were not entirely consistent across agencies. For example, the Food and Drug Administration (FDA) allows containers to be sold by “net quantity” of “volume or weight.” The Environmental Protection Agency (EPA) regulations stipulate that the “net contents of BOV pesticide products must be expressed in terms of both liquid measure and weight.” And the Federal Trade Commission (FDC) guidelines require that the label state the “net quantity” of the content, without specifying if this statement refers to volume or weight. At the point of sale, having the quantities labeled in so many different ways makes value comparison very difficult for the consumer.

"So the Laws and Regulations committee of the NCWM recommended that NIST facilitate a meeting of all the concerned parties," Sefcik said. "And that's what we did – invite all stakeholders together, in an effort to educate them regarding the issue and to reach a consensus on the proper method of sale."

On January 9, 2017, that meeting – headed by NIST – took place, with representatives from various aerosol companies, trade associations and the FDA, FTC, EPA and other agencies present. After exhaustive presentations and discussions, Sefcik reported, "we were able to reach a unanimous consensus that the products should be sold by weight."

"The report on that meeting became the basis for a recommendation to the NCWM that products using BOV technology be sold by weight in accordance with current federal and state regulations. It was also recommended that current language in NIST Handbook 130's section on aerosols and pressurized containers be revised and clarified,” Sefcik added.

The newly clarified language will be put to a vote in July of 2017 at the NCWM's 99^th annual meeting. A three year grace period will be given to manufacturers to re-label their products and for the Federal agencies to make their regulations more consistent.

"It's as fair as it can be," Sefcik concluded. "The BOV companies won't have to distinguish themselves from aerosols. And consumers will be able to make rational purchasing decisions and value comparisons based on a common method of sale."