Zinc Chromate in Marine Coatings

When it comes to protecting your propellers and underwater metals from marine growth, not all products are created equal. While most boat owners focus on performance and longevity, it’s equally important to understand what’s inside the coatings you’re applying — and how those ingredients can affect your health and the environment.

One such ingredient, found in some popular foul-release systems (such as two-part etch primers), is zinc chromate.

What is Zinc Chromate?

Zinc chromate is a bright yellow, corrosion-inhibiting pigment once widely used in primers for aircraft, ships, and metal structures. It’s highly effective at preparing metal surfaces for paint adhesion and preventing rust — but that performance comes at a significant cost to human health.

Why It’s Dangerous

Zinc chromate contains hexavalent chromium (Cr(VI)), a substance recognised worldwide as:

• Carcinogenic – Linked to lung cancer and other cancers after inhalation exposure.
• Toxic to skin and eyes – Can be absorbed through skin contact and cause ulceration or dermatitis.
• Harmful to the respiratory system – Inhalation of dust, mist, or fumes can cause irritation, nosebleeds, coughing, and long-term lung damage.
• Persistent in the environment – Once released, hexavalent chromium compounds can remain toxic in soil and water.

These risks are so serious that many industries have phased out zinc chromate, and strict handling protocols are required in the few sectors where it’s still used.

Where You’ll Find It in Marine Use

Some propeller coating systems rely on a two-part etch primer containing zinc chromate to achieve adhesion. Applying these products often involves sanding, spraying, or brushing — all activities that can release hazardous particles or vapours. Without full protective gear (respirator, gloves, goggles, and coveralls), users risk dangerous exposure.

Even after application, future sanding or removal of the coating can re-expose workers and boat owners to toxic dust.

A Safer Alternative: Velox Plus

At Boating Products, we import and supply Velox Plus, a specialised antifoul for propellers and underwater metals. The Velox Plus system does not include zinc chromate, and so does not carry the same carcinogenic classification as hexavalent chromium compounds.

Velox Plus:

• Does not require hazardous two-part etch primers.
• Is easier and safer to apply.
• Provides lasting protection against marine growth without compromising health or safety.

The Bottom Line

While performance on the water matters, so does safety on the dock. Understanding the chemistry behind your coating choice can protect not just your boat — but your health, your crew, and the marine environment.

When you next choose a propeller coating, ask yourself: Do I want a product that works because of a known carcinogen, or one that works without one?