Seventh Generation has launched a campaign urging people to "say no to the glow" in relation to clothes washing detergent.

The company says optical brighteners are a laundry detergent additive that trick our eyes into perceiving clothes being whiter and brighter than they actually are - and this optical illusion doesn't mean the clothes are cleaner. 

Here's how a laundry detergent with optical brighteners looks under ultra violet light - UV rays are a part of sunlight and you can see why optical brighteners are so good at what they do:

Image credit: Michele M. Ferrario

The chemicals involved pose health issues for humans and the wider environment says Seventh Generation. 

A significant amount of optical brightening agents are left behind on clothes after washing. These chemicals can then irritate skin, causing a rash.

Up to 47% of the chemicals go down the drain during the washing cycle and are not filtered out during wastewater treatment processes - so they wind up in our waterways. They don't completely biodegrade, can be toxic to algae and small fish and bio- accumulate in larger fish.

Seventh Generation maintains that optical brighteners are not necessary to formulate a high performance laundry detergent. If you're not sure if the detergent you use has optical brighteners; it may be mentioned on the label - but this isn't always the case; so you should contact the company that makes the detergent for clarification.

Our laundry detergents tend to be a mish-mash of all sorts of chemicals - optical brighteners aren't the only environmental concern. There's surfactants, builders, bleaches, colorants, fragrances and solvent ingredients; some of which are synthesized from crude oil. There just seems to be no escape from our reliance on fossil fuels.

However, you can certainly lighten the impact of your laundry activities. Learn more about more environmentally friendly clothes washing.