EPA looks to restrict formaldehyde use in urea fertilizer

Formaldehyde is an essential ingredient in the production of urea fertilizer, but an Environmental Protection Agency occupational exposure value ruling on the substance, could threaten its use in agriculture. In March 2024, the EPA released a draft risk evaluation under the Toxic Substances Control Act for formaldehyde for public comment and peer review.

The EPA preliminarily determined that formaldehyde poses an unreasonable risk to human health. The EPA has not previously set a broad OEV for formaldehyde. If this EPA evaluation is approved, formaldehyde restrictions or a ban on the substance, could create challenges for farmers.

Formaldehyde is a naturally-occurring substance, consisting of carbon, hydrogen and oxygen. According to the American Chemistry Council, humans produce about 1.5 ounces of formaldehyde gas each day due to metabolism. Formaldehyde is also created as a result of combustion and produced at a large scale by catalytic, vapor-phase oxidation of methanol.

Formaldehyde is commonly associated with the embalming process, but it is also used in a variety of products, including building materials, adhesives, fungicide, germicide, vaccines, household products and urea fertilizer. The EPA classifies formaldehyde as a “probable human carcinogen” and a “high priority chemical,” therefore the agency can regulate its use.

Formaldehyde in fertilizer

Reagan Giesenschlag, director of government affairs at The Fertilizer Institute, referred to formaldehyde as an essential building block in organic chemistry that is used widely in manufacturing. For the fertilizer industry, formaldehyde is used as a conditioning agent to granulate solid urea, slow-release urea and urea triazone liquid slow-release fertilizers.

“It is essential for us to be able to granulate urea with a hardness and at a size that is comparable to the other P and K nutrients, so that we’re able to blend it and only have to do one application on the fields,” Giesenschlag said.

Giesenschlag said prior to the use of formaldehyde-based reactants, urea was soft, powdery and would produce dust, making it difficult to transport and handle when applying to a field. The U.S. Department of Agriculture conducted research that showed formaldehyde was an ideal conditioning agent for urea and it became popular starting in the mid-1960s.

“We’ve been using this technology for a long time, and it’s allowed urea to be more broadly used as a nitrogen source in ag,” Giesenschlag said. “Urea is the highest content, solid-form of nitrogen we have. We don’t have any viable alternatives for formaldehyde in the granulation process for urea at this point.”

For context, Giesenschlag said urea makes up about 25 to 30% of the nitrogen used in the U.S. Globally, urea amounts to about 50% of the nitrogen used worldwide and the U.S. produces about 55% of the urea that is used domestically.

“In 1981, about 5 million tons of urea were produced domestically here in the U.S., and today that has increased to about 8.5 million tons,” she said.

For the manufacturing of urea, Giesenschlag said small amounts of formaldehyde-based reactants are introduced into the reactor with molten urea, which allows for longer chain molecules to be granulated into hard, uniform particles. The urea binds with the formaldehyde and completely transforms it into new chemical structures. During this process, all the formaldehyde is consumed.

“There is no free formaldehyde present in the final products that our farmers or ag retailers are handling,” Giesenschlag said.

Giesenschlag said urea-formaldehyde fertilizers are safe and easy for farmers to apply to their fields and it does not require any specialty equipment, making this a valuable fertilizer product for agriculture.

The EPA’s proposal and potential impacts

In the risk evaluation for formaldehyde, the EPA published a recommendation of an OEV of 11 parts per billion.

“That’s lower than what is in 50% of homes in the U.S., and lower than background in a lot of situations,” Giesenschlag said. “It’s also about 30 times lower than the European Union’s standard for formaldehyde that was recently revised. When the EU redid its risk evaluation for formaldehyde and occupational exposures, regulators did not find a risk in the final user of fertilizer products.”

Giesenschlag called the proposal unrealistic and overly conservative. She said the EPA’s evaluation is even more problematic considering the EU has historically been much stricter about chemical constraints than the U.S. Even though both parties had access to the same science and health studies, they came to opposite conclusions.

For perspective, the median lethal dose of formaldehyde in humans is 600 to 800 milligrams per kilogram of body weight. In comparison, the median lethal dose of caffeine for humans is 150 to 200 milligrams per kilogram of body weight.

“If they (EPA regulators) finalize the evaluation, then they have a year to come out with a risk management rule for all of those risk determinations,” Giesenschlag said. “If the unreasonable risk determination for occupational use of urea is upheld, then that would have to enter risk management and be subject to a potential ban or Workplace Chemical Protection Program.”

According to Giesenschlag, a protection plan could include respirators or full-face respirators for anyone working in ag retail or farmers handling fertilizer. Possible consequences of formaldehyde restrictions in the agriculture industry include scarcity of nitrogen in general, lower crop yields and higher food prices.

“We are concerned that if they maintain unreasonable risk determinations for the fertilizer industry, it could impact our ability to produce urea domestically,” Giesenschlag said. 

Giesenschlag said the U.S. primarily imports 45% of its domestically used urea from countries like Russia, Saudi Arabia, Algeria and Qatar. Formaldehyde restrictions could leave farmers reliant on those countries, bringing up demand, along with the price.

“We don’t want to be dependent on imports from places like Russia, and we don’t want to see overly stringent workplace standards placed on farmers when there’s not a real established risk for them,” Giesenschlag said. “A lot of the assumptions that the EPA have made of our industry and the chemistry around fertilizer products is just way off base. We were shocked by the unreasonable risk determination for the actual final products themselves. We attempted to provide corrections to their erroneous assumptions, but with the rush that they are in to try and finalize this by the end of the year, it’s unlikely we’ll see many changes in the final risk evaluation.”

Giesenschlag said if the EPA’s recommendations are passed, litigation is an option, but there will be many challenges to overcome the EPA’s decisions.

“We are engaging in the process trying to provide them the best information, so they don’t go forward with these unreasonable regulations,” she said.

Lacey Vilhauer can be reached at 620-227-1871 or [email protected].