The safety of marine antifreeze is a common concern, particularly regarding its potential effects on the environment and human health. Its toxicity is not straightforward, as it largely depends on the specific chemical composition. Different types present varying levels of risk, necessitating a clear understanding of their properties.
Different Types of Marine Antifreeze
Marine antifreeze typically uses one of two primary compounds: propylene glycol (PG) or ethylene glycol (EG). Ethylene glycol (EG) is a clear, odorless, viscous liquid often used in automotive antifreeze due to its thermal properties and low freezing point. It has a sweet taste, which can attract animals and children.
Propylene glycol (PG), in contrast, is also a clear, viscous, nearly odorless liquid with a faintly sweet taste. It is commonly used in marine and RV applications and is often colored pink or blue for identification. Propylene glycol is considered less toxic than ethylene glycol, making it preferred for systems where incidental human or animal contact might occur, such as boat potable water systems. Both types lower water’s freezing point to prevent pipe damage, but their toxicity profiles differ significantly.
Potential for Harm
Ethylene glycol is toxic to humans and animals upon ingestion. When metabolized, it produces toxic compounds that can cause severe health issues, including central nervous system depression, cardiopulmonary effects, and acute kidney failure, which can be fatal. Symptoms in humans range from intoxication and vomiting to seizures and brain damage. In pets, particularly dogs and cats, ingestion is dangerous due to its sweet taste, leading to kidney damage and potential death within hours or days.
Propylene glycol, while less toxic, can still cause harm in high concentrations. In humans, large oral doses can lead to central nervous system depression, metabolic acidosis, and, in severe cases, acute kidney injury. In the environment, propylene glycol is biodegradable, but large spills can deplete oxygen levels in water as microorganisms break it down. This oxygen depletion can negatively affect aquatic organisms.
Protecting People and the Environment
Caution is important when handling marine antifreeze to protect individuals and the environment. Always read and follow the manufacturer’s instructions on the product label for proper use and disposal. When working with antifreeze, wear appropriate personal protective equipment, such as gloves, and ensure adequate ventilation to minimize exposure.
Store antifreeze in its original, clearly labeled container in a cool, dry place to prevent leaks and accidental ingestion. Antifreeze should never be poured onto the ground, into storm drains, or into waterways, as it can contaminate soil and water sources.
Instead, collect used antifreeze in secure containers and take it to a marina, automotive center, or local recycling facility that accepts used coolants. Some facilities differentiate between pure and contaminated antifreeze, so know if the used product contains other substances like oil or heavy metals, which would classify it as hazardous waste.