No Bleach Near Water: Protecting Our Sea Steps, Slipways and Marine Life

When families began reporting the smell of bleach on sea steps and slipways around Ireland, Coastwatch took notice. Parents told us that their children complained of burning skin after using recently cleaned sea access points. Others reported finding marine life dead on rocks near treated areas.

What began as a local concern quickly became a national environmental issue.

Today, Coastwatch is calling on everyone who cleans or maintains sea steps, slipways and coastal promenades to stop using bleach and bleach-based products near water. Not only is the practice harmful to marine life, it is also illegal under Irish water pollution legislation and poses risks to human health.

A New Awareness Campaign

To help spread this important message, Coastwatch has launched its new "No Bleach Near Water" campaign poster. The poster was unveiled by renowned sailor and explorer Enda O'Coineen aboard the Spirit of Shackleton in Dún Laoghaire Harbour.

The poster was designed by Coastwatch student intern Elise Merckel, who recognised that many people may simply be unaware of the damage caused by sodium hypochlorite—the active ingredient in most bleach products.

"I designed this as an alert poster so sodium hypochlorite, commonly known as bleach, will no longer be used on slipways, sea promenades and sea steps," said Elise. "It's not just an Irish problem. Perhaps the poster should be translated and shared more widely."

Why Bleach Is a Problem

Bleach is highly effective at removing algae and seaweed, which is why it has become a common cleaning solution in some coastal areas. However, its effectiveness comes at a cost.

Sodium hypochlorite is a hazardous chemical that can kill a wide range of marine organisms. It is classified as corrosive, requiring protective equipment such as gloves and safety clothing during use. Yet sea steps and slipways are often used by children and families shortly after cleaning takes place.

Irish legislation is clear. The Local Government (Water Pollution) Act prohibits the entry of polluting matter into waters. Despite this, Coastwatch's national survey of sea-step and slipway maintenance practices in 2024 found bleach-based products being used in several counties.

Looking for Better Solutions

Rather than simply highlighting the problem, Coastwatch wanted to find practical alternatives.

Through the Horizon Europe more4nature project, Coastwatch partnered with Dún Laoghaire-Rathdown County Council, Sandycove Kayak Club and Bunzl Ireland to test environmentally responsible cleaning methods.

Volunteers cleaned test areas using combinations of brushes, water, sand and non-hazardous cleaning products. The results were encouraging.

What We Learned

Hazardous chemicals are not necessary

Sample areas were successfully cleaned without bleach. Five weeks later, indicator limpets living beside the sea steps remained in place, suggesting the cleaning process had not harmed local marine life.

Brush design matters

Steel brushes proved more effective than natural-fibre alternatives, although volunteers found them difficult to handle. Future efforts should focus on developing more ergonomic steel brushes designed specifically for marine cleaning.

Sand helps

Adding sand significantly increased the abrasive power of brushing, making it easier to remove algae and biofilm.

Maintenance becomes easier over time

The first cleaning required the greatest effort. Once established growth was removed, subsequent cleaning sessions became quicker and less labour-intensive.

Water management is critical

Nutrient-rich seepage water draining onto slipways can accelerate algae growth between cleaning cycles. Addressing drainage issues and sealing cracks can significantly reduce future slip hazards.

Building Awareness and Compliance

Coastwatch believes that education is just as important as enforcement.

We would like to see warning posters displayed at harbours, bathing waters and coastal access points, helping volunteers, sports clubs and members of the public understand both the environmental impacts and legal responsibilities associated with coastal cleaning.

Local authorities also have a role to play by ensuring staff and contractors understand that hazardous chemicals should not be used near coastal waters.

Time to Celebrate Good Practice

Rather than focusing solely on problems, Coastwatch would also like to recognise positive examples.

Imagine an annual award for Ireland's best-maintained slipways and sea steps:

• Best Ecological Design

• Best Environmentally Friendly Maintenance

• Best Community Stewardship

Such recognition could encourage innovation while highlighting practical solutions that protect both public safety and marine ecosystems.

Watch Out for Misleading Products

One ongoing concern is the continued sale of products marketed as "seaweed removers" that contain bleach or other hazardous chemicals.

Coastwatch is calling on government agencies to investigate misleading marketing claims and ensure products are not promoted for uses that may breach environmental regulations.

Consumers can help by checking labels carefully. If a product contains sodium hypochlorite (NaOCl), it should not be used near coastal waters.

Protecting Our Shores Together

Ireland's coast is one of our greatest natural assets. Slipways and sea steps help us enjoy it safely, but maintaining them should never come at the expense of marine life.

The good news is that environmentally responsible alternatives work.

By choosing brushes, water, sand and non-hazardous cleaning methods, we can keep coastal access points safe while protecting the ecosystems that make our shores so special.

The full cleaning experiment report and practical recommendations are available from Coastwatch.

Together, we can keep our coasts safe—for people and for nature.

Download the full press release here.

View the Irish Times article by Caroline O Doherty here.

Seasteps as seen from the point of view of nature - beauty and the bleach beast . One steps and pier maintained by nature the other by men with bleach. Photos by Karin Dubsky

Photos by Dylan K.