Several beaches in France's northwest have been closed due to worries that toxic seaweed, blamed in the deaths of dozens of wild boar, could be a hazard to humans.

The phenomenon occurs when runoff of excess fertilizer enters the ocean, prompting a rapid growth of seaweed that then washes up on the shore. Once on land, it releases toxic gases as it rots.

Environment Minister Nathalie Kosciusko-Morizet ordered the beaches along the coast of Brittany closed several weeks back, but the problem persists.

According to Radio France Internationale, Kosciusko-Morizet argued that farming practices were largely to blame for the excess fertilizer, and that a balance needed to be met between the demands of farming and the demands of tourism.

Have a look at Brittany's green beaches below:

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An information placard about masses of green seaweed along the French coastline is seen on a beach at Kerlaz near Douarnenez in Brittany, western France, August 30, 2011. REUTERS
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A handful of seaweed is displayed as masses of green seaweed, which at times emits noxious gasses, is seen on Kerlaz beach near Douarnenez in Brittany, western France, August 30, 2011. REUTERS
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Seagulls search for food amongst seaweed on a beach at Kerlaz near Douarnenez in Brittany, western France, August 30, 2011. REUTERS
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A closeup of a clam amongst the seaweed during low tide on Kerlaz beach near Douarnenez in Brittany, western France, August 30, 2011. REUTERS
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A communal beach patrol vehicle drives on masses of green seaweed, which at times emits noxious gasses, at Kerlaz beach near Douarnenez in Brittany, western France, August 30, 2011. REUTERS
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Masses of green seaweed, which at times emits noxious gasses, is seen on a beach at Kerlaz near Douarnenez in Brittany, western France, August 30, 2011. REUTERS
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A wet dog returns to its master over masses of seaweed at low tide on Kerlaz beach near Douarnenez in Brittany, western France, August 30, 2011. REUTERS
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