Ammonia has been a staple in cleaning products for decades, valued for its streak-free finish and grease-cutting ability. It is also a strong respiratory irritant that produces toxic chloramine gas when mixed with bleach, a combination that happens in households every year because both products are stored under the same sink. The CDC and poison control centers document these mixing incidents annually. The No Nines™ Standard™ excludes ammonia from all No Nines™ products, not because it does not clean, but because the respiratory risks and mixing hazards are unnecessary when better alternatives exist.
What is ammonia in cleaning products?
When cleaning product labels list ammonia, the actual ingredient is ammonium hydroxide: ammonia gas dissolved in water. Household cleaning products typically contain ammonia at concentrations between 5% and 10%. At these concentrations, it functions as an effective degreaser and produces a streak-free finish on glass and mirrors, which is why it has been a primary ingredient in glass cleaners for generations.
Ammonia evaporates quickly from surfaces, which contributes to its streak-free performance. That same volatility is also the source of its primary health concern: when ammonia evaporates, it becomes airborne, and you breathe it in.
You will find ammonia in glass cleaners, floor cleaners, oven cleaners, and some multi-surface sprays. It is one of the most common cleaning chemicals in both household and commercial settings. The Occupational Safety and Health Administration (OSHA) sets the permissible exposure limit for ammonia at 50 ppm over an eight-hour workday. The American Conference of Governmental Industrial Hygienists recommends a stricter limit of 25 ppm. For context, you can typically smell ammonia at concentrations between 5 and 50 ppm, meaning that by the time you notice the smell, you may already be at or near occupational exposure limits.
What the research says
Ammonia is classified as a severe respiratory irritant. The Agency for Toxic Substances and Disease Registry (ATSDR) reports that exposure to ammonia concentrations between 2.3 and 20.7 ppm is associated with bronchial reactivity, inflammation, cough, wheezing, shortness of breath, and measurable decrements in pulmonary function. These are concentrations that can be reached during normal use of ammonia-based cleaning products in enclosed spaces.
The ATSDR established a chronic-duration inhalation minimal risk level of just 0.1 ppm for ammonia. Exposures above 50 ppm cause immediate irritation to the nose and throat. Higher concentrations can cause nasopharyngeal and tracheal burns, airway obstruction, and pulmonary edema.
According to the ATSDR, ammonia exposure between 2.3 and 20.7 ppm is associated with bronchial reactivity, cough, wheezing, and shortness of breath.
The occupational data on cleaning workers is substantial. A workforce-based study published in the Annals of Occupational Hygiene (2011) found that cleaning workers reported exposure to at least one strong irritant, including ammonia, on 56% of working days, and that ammonia use was specifically associated with increased asthma symptom scores. A 2011 review in Current Opinion in Allergy and Clinical Immunology identified cleaning work as one of the occupations with the highest risk for occupational asthma, with ammonia listed among the primary irritant exposures.
Ammonia is a recognized asthmagen. It can both trigger asthma symptoms in people with existing asthma and contribute to the development of new-onset asthma through repeated occupational or household exposure. Eye and skin irritation are also well documented at household-relevant concentrations.
The environmental profile of ammonia adds another dimension. The EPA maintains Aquatic Life Criteria for Ammonia because it is directly toxic to aquatic organisms, particularly freshwater mussels and snails. Unlike nutrients that cause indirect harm through algal overgrowth, ammonia causes direct toxic effects, including gill damage and reduced growth rates, at concentrations of just a few parts per million. When ammonia-based cleaning products go down the drain, they contribute to this aquatic toxicity burden.
The bleach-ammonia mixing hazard
The most acute risk associated with ammonia in cleaning products is not ammonia itself. It is what happens when ammonia meets bleach.
When ammonia-based cleaners are mixed with bleach (sodium hypochlorite), the chemical reaction produces chloramine gas. Chloramine gas exposure causes chest pain, shortness of breath, coughing, nausea, and watery eyes. At higher concentrations, it can cause pneumonia and pulmonary edema (fluid in the lungs). Severe exposures can be fatal.
This is not a rare occurrence. A 2024 study published in Clinical Toxicology analyzed data from America's Poison Centers' National Poison Data System and found that total reported exposures to chlorine and chloramine gas increased by 61% between 2015 and 2022, from 8,385 to 13,503 reported cases per year. The largest single-year increase, 38.3%, occurred between 2019 and 2020, likely driven by increased household cleaning during the COVID-19 pandemic. The elevated numbers persisted through 2022.
Chlorine and chloramine gas exposures reported to U.S. poison centers increased 61% between 2015 and 2022, reaching 13,503 reported cases in 2022.
The mixing scenario is common because it is easy. Both ammonia-based cleaners and bleach-based cleaners are stored under the kitchen or bathroom sink. A person cleans one surface with an ammonia glass cleaner, then reaches for a bleach-based bathroom cleaner. Or a well-meaning household member mixes two products together, believing more chemicals equals more cleaning power. The resulting gas is produced immediately and in an enclosed space.
Ammonia mixed with acidic cleaners presents a different hazard: the acid liberates ammonia gas from the solution more rapidly, increasing airborne concentration. This reaction is less well known than the bleach interaction, making it more likely to catch people off guard.
Product labels do carry mixing warnings, but they are typically small, buried in fine print, and use generic language like "do not mix with other cleaners." They do not prominently identify which specific products are dangerous to combine. The burden of chemical safety knowledge falls entirely on the consumer, who is expected to understand the chemistry of every product under their sink.
The better approach is not "be careful." The better approach is products that do not create the hazard in the first place.
Why ventilation is not a solution
The standard advice for using ammonia-based products is to ensure adequate ventilation. Open a window. Turn on a fan. This advice treats a product design problem as a user behavior problem.
Consider where cleaning products are actually used. Bathrooms are small, enclosed spaces. Many have no window at all, only a ventilation fan that may or may not be functional. Kitchens offer more airflow, but ammonia-based oven cleaners are used inside an oven, which is about as enclosed as a space gets. Cleaning in winter means windows stay closed.
Even when ventilation is available, the exposure happens before the ventilation takes effect. Spraying an ammonia-based glass cleaner releases ammonia immediately. You are standing directly over the product when you apply it. The first breath contains the highest concentration. Opening a window afterward reduces ongoing exposure but does not eliminate the initial inhalation.
The ATSDR's chronic minimal risk level for ammonia is 0.1 ppm. The idea that opening a window reliably keeps exposure below 0.1 ppm while using a product that contains 5% to 10% ammonia is not realistic for most cleaning scenarios.
Shifting the safety burden to the user, requiring specific ventilation behavior, knowledge of mixing chemistry, and awareness of exposure limits, is a design choice by the product manufacturer. A cleaning product that requires respiratory precautions for normal use is a product that could be formulated differently.
What No Nines uses instead
No Nines products clean surfaces, including glass, without ammonia. The Whole Home HOCl Cleaner is built on hypochlorous acid (HOCl), which delivers effective surface cleaning with a streak-free finish on glass and mirrors. It requires no ventilation precautions during use. It does not produce fumes. It does not create a mixing hazard.
The absence of ammonia across the entire No Nines product line also eliminates the mixing hazard entirely. There is no ammonia in any No Nines product. There is no bleach in any No Nines product. The two most dangerous household cleaning chemical combinations simply cannot happen if neither chemical is present. You do not need to remember which products are dangerous to combine, because none of them are.
This extends to every product in the line. The Sink + Drain Refresher, Washer Refresh, and Pet Deodorizer all clean and deodorize without ammonia or bleach. The Foaming Hand Wash and Laundry Rinse are formulated without respiratory irritants. No product in the No Nines line requires ventilation warnings.
The goal is not to make cleaning slightly less hazardous. The goal is to remove the hazard from the equation.
The bottom line
Ammonia is a respiratory irritant at concentrations achievable during normal household cleaning. It is an established contributor to occupational asthma among cleaning workers. When mixed with bleach, it produces chloramine gas, a scenario that sent more than 13,000 people to poison control in a single year. It is toxic to aquatic life at low concentrations.
These risks exist because ammonia-based products were designed decades ago, before we had better options. Those better options now exist. HOCl cleans glass, removes grease, and works on all surfaces without fumes, without mixing hazards, and without requiring the user to manage their own respiratory safety.
No Nines excludes ammonia as one of the nine chemical categories in the No Nines Standard, not because ammonia cannot clean, but because it does not need to.
Shop ammonia-free, bleach-free cleaning products.
This is post 8 of 9 in the Nasty Nine series. Read more about bleach in cleaning products (Post 6) and quaternary ammonium compounds in cleaning products (Post 1).
