Does regular room lighting cause Lego to yellow?

[Aethersprite]

Hello all! I've recently got into collecting Star Wars sets, and I've started displaying them in my cupboard (which has a transparent glass door). As I have quite a few sets with many white bricks (the Headhunter, RGS, etc), I'm quite worried about them yellowing over time. The windows in my room where I display my sets do have a special UV protection film applied on them though, so I'm not too worried about sunlight causing yellowing. Does anyone know if regular room light will cause Lego bricks to yellow? Most of the stuff I've found online have to do with sunlight but say little about regular room light. Thanks in advance!

Edited March 22, 2014 by Lockon Stratos

[JopieK]

The problem is inconsistencies in the material. LEGO Service says that to reverse the effect one needs to put it in direct sunlight even! Even unopened boxes do have yellowed parts. Heat is a larger problem I think, that is why I always have blinds closed...

[62Bricks]

The yellowing of parts is caused by a chemical LEGO formerly added to the plastic as a fire retardant (bromine) that reacted with ultraviolet light. They no longer use that chemical, although I'm not sure when they stopped. Modern sets shouldn't have the same problem with yellowing as those from the 70s and 80s when the chemical was used.

All light bulbs emit some ultraviolet light. Incandescent bulbs emit very little UV light. Flourescent light bulbs do emit UV light and can yellow plastic that contains the bromine-based fire retardant. In the case of old-style flourescent tube lighting, there are commercially available clear plastic sleeves that will block the UV light (library supply catalogs will have them - they use them to reduce the UV effect of flourescent lights on paper). As for the newer compact flourescent bulbs, I'm not sure if there are types that are designed to reduce or block UV light.

[Vee]

The yellowing of parts is caused by a chemical LEGO formerly added to the plastic as a fire retardant (bromine) ...

Gatorade also uses fire retardant (bromine) in their beverages...

[badbob001]

In the room where I have my LEGO displayed, I've replaced all the compact-florescent bulbs with LED bulbs. I also plan to put UV-blocked sheets over the window panes.

[Faefrost]

The yellowing of parts is caused by a chemical LEGO formerly added to the plastic as a fire retardant (bromine) that reacted with ultraviolet light. They no longer use that chemical, although I'm not sure when they stopped. Modern sets shouldn't have the same problem with yellowing as those from the 70s and 80s when the chemical was used.

All light bulbs emit some ultraviolet light. Incandescent bulbs emit very little UV light. Flourescent light bulbs do emit UV light and can yellow plastic that contains the bromine-based fire retardant. In the case of old-style flourescent tube lighting, there are commercially available clear plastic sleeves that will block the UV light (library supply catalogs will have them - they use them to reduce the UV effect of flourescent lights on paper). As for the newer compact flourescent bulbs, I'm not sure if there are types that are designed to reduce or block UV light.

It's not that they don't add Fire Retardent. They are required by law to add certain fire retardents to plastic toys in the US, Canada and parts of Europe. But the chemicals that they use and the amounts they use have changed and evolved over the years. So different vintage bricks and even same vintage bricks from different batches of plastic will discolor to a wide degree of variance. Modern bricks should not discolor as much or as fast. But they will all discolor some. It's just how it goes. And as others have said it is primarily just a chemical reaction. Light and air contact will make it happen faster, but it will eventually happen.

[62Bricks]

It's not that they don't add Fire Retardent. They are required by law to add certain fire retardents to plastic toys in the US, Canada and parts of Europe. But the chemicals that they use and the amounts they use have changed and evolved over the years. So different vintage bricks and even same vintage bricks from different batches of plastic will discolor to a wide degree of variance. Modern bricks should not discolor as much or as fast. But they will all discolor some. It's just how it goes. And as others have said it is primarily just a chemical reaction. Light and air contact will make it happen faster, but it will eventually happen.

I don't know of any laws that require flame retardants in children's toys. In fact, the opposite is true regarding several types of flame retardant - many US states are banning their use in children's toys because of possible toxic exposure.