Propylene glycol is one of the most widely used chemical compounds in the food, pharmaceutical and refrigeration industries, and a common question among those handling it for the first time is whether it is a toxic product. The answer is that propylene glycol has very low toxicity compared with other industrial glycols, such as ethylene glycol, and is classified as safe for use in food and cosmetics when used at the appropriate concentrations and grades. However, like any chemical product, it requires some minimum safe-handling guidelines that are worth knowing.
Is propylene glycol toxic
The toxicity of propylene glycol is considerably lower than that of other compounds in the same chemical family. While ethylene glycol is highly toxic even in small ingested amounts, propylene glycol has been evaluated by international regulatory bodies and classified in the GRAS category (Generally Recognized As Safe) by the US FDA for use as a food additive, and it is authorised in the European Union under the code E1520.
This does not mean that propylene glycol is harmless in all circumstances: its safety profile depends on the route of exposure, the concentration and the duration of contact. At very high doses and over prolonged periods, any chemical substance can cause adverse effects, and propylene glycol is no exception, although its margin of safety is notably greater than that of other industrial solvents and glycols.
Health effects of propylene glycol
To understand whether propylene glycol is bad for health or not, it is necessary to distinguish according to the route of exposure. The effects for each type of contact are detailed below.
Skin contact
Propylene glycol is considered a low-irritation product for the skin in most people, which is why it is commonly used as an excipient in creams and cosmetics. However, in people with sensitive or predisposed skin, a propylene glycol allergy may occur in the form of contact dermatitis, with symptoms such as redness, itching or localised irritation. If a skin reaction is detected after contact with products containing propylene glycol, it is recommended to wash the area with plenty of water and consult a healthcare professional if the irritation persists.
Eye contact
Direct contact with the eyes can cause mild irritation, with a stinging sensation or watering. It is not considered corrosive to eye tissue, but the use of protective goggles is recommended during industrial handling, especially when working with large volumes or in transfer processes.
Inhalation
Due to its low volatility, propylene glycol does not generate significant vapours under normal temperature conditions, so the risk from inhalation is limited compared with other industrial solvents. In processes involving heating or misting of the product, mild irritation of the respiratory tract can occur, which is why adequate ventilation is recommended in these specific applications.
Accidental ingestion
Ingesting small amounts of USP- or food-grade propylene glycol does not pose a serious health risk, which is why it is authorised as a food additive. However, ingesting large volumes of technical or industrial product is not without risk and requires medical attention. In the event of accidental ingestion of significant amounts, the advisable course of action is to contact the Toxicology Information Service or go to a medical centre, taking the container or the product’s safety data sheet with you if possible.
Is propylene glycol carcinogenic
Propylene glycol is not classified as a carcinogenic substance by the International Agency for Research on Cancer (IARC) or by other leading regulatory bodies. This is one of the most important differences compared with other chemical compounds for industrial use that do have more severe hazard classifications. Its favourable toxicological profile is precisely what has allowed its authorisation as a food additive and its widespread use in pharmaceutical and cosmetic formulations.
Propylene glycol safety data sheet
All professional handling of propylene glycol must be based on the product’s safety data sheet (SDS), a mandatory document that the supplier must provide and that contains the information needed for safe handling:
- Hazard identification: classification under the CLP Regulation and applicable safety pictograms, if any.
- Composition: purity and possible impurities or additives depending on the product grade (USP, food or technical).
- First-aid measures: protocol to follow in case of skin or eye contact, inhalation or ingestion.
- Handling and storage measures: temperature conditions, compatibility with other materials and storage recommendations.
- Recommended personal protective equipment: gloves, goggles and, where applicable, respiratory protection depending on the application.
- Toxicological and ecological information: data on its behaviour in the body and in the environment.
Before working with any batch of propylene glycol, it is essential to request the up-to-date safety data sheet from the supplier and keep it accessible in the workplace.
How to handle propylene glycol safely
Although its risk profile is low, following some basic handling guidelines ensures safe use in both industrial environments and smaller-scale professional applications:
- Use the right grade for each application: USP propylene glycol for food, pharmaceutical or cosmetic use; technical propylene glycol for industrial applications without direct contact with people or food.
- Use basic protective equipment: chemical-resistant gloves and safety goggles during transfer or handling of large volumes.
- Avoid prolonged skin contact: even though it is not highly irritating, minimising exposure reduces the risk of long-term sensitisation.
- Store under suitable conditions: in a cool place, away from direct heat sources, in tightly closed and properly labelled containers.
- Always consult the safety data sheet before using the product for the first time or when the supplier or the product grade changes.
If your company needs propylene glycol for food, pharmaceutical or industrial applications, at CH Química we offer USP propylene glycol with an up-to-date safety data sheet and technical advice on the most suitable grade for each use. Also take a look at our complete range of industrial glycols or contact us for personalised advice.
Frequently asked questions about propylene glycol safety
Is propylene glycol toxic?
Propylene glycol has very low toxicity compared with other industrial glycols such as ethylene glycol. It is classified as GRAS by the FDA for food use and authorised in the European Union as additive E1520. Its safety profile depends on the route of exposure and the concentration, but under normal conditions of use it does not represent a relevant health risk.
Is propylene glycol carcinogenic?
No, propylene glycol is not classified as a carcinogenic substance by the International Agency for Research on Cancer (IARC) or by other leading regulatory bodies. This favourable toxicological profile is one of the reasons why its use is authorised in food, pharmaceuticals and cosmetics.
Can propylene glycol cause a skin allergy?
In people with sensitive or predisposed skin, contact with propylene glycol can cause contact dermatitis, with symptoms such as redness, itching or localised irritation. It is not a common allergen, but a prior patch test is recommended if it is going to be used continuously on the skin, and the area should be washed with plenty of water if irritation appears.
What should you do in case of accidental ingestion of propylene glycol?
Ingesting small amounts of USP-grade or food-grade propylene glycol does not usually pose a serious risk. However, if significant amounts of technical or industrial product are ingested, it is advisable to contact the Toxicology Information Service or go to a medical centre, bringing the container or the product’s safety data sheet if possible.
What protective equipment is needed to handle propylene glycol?
For professional handling of propylene glycol, chemical-resistant gloves and safety goggles are recommended, especially during transfer or when handling large volumes. Although its risk profile is low, following these basic measures minimises any unnecessary exposure and is standard practice when handling industrial chemical products.