# Add a special effect for the CO2 option

To reinforce the fact that CO2 is not a good choice for a paper fire, we’ll add an explosion if the user chooses that option.

1. On the timeline, select the cog icon for the `paper_co2` button.
2. In the **Triggered Effects** section, select **Trigger For**, so that **Everyone** changes to **Local User**.
3. Select **NEW**.
4. From the type of effect options, select IFX.
5. In the search field, enter explosion, and then select the search icon.
6. Select the **Explosion (huge)** IFX, and place it at the center of the papers.

{% hint style="info" %}
It can be difficult to position the explosion because it's only briefly visible. However, when you choose to edit the trigger effect, the explosion will be the only object bubble that's visible.
{% endhint %}

<figure><img src="https://3460182399-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FwVx6bvwqEE7tD0TYOcfj%2Fuploads%2Fgit-blob-3d24507bd06f1da2d3e1774831db8c833de44876%2Ftut_train_explosion_bubble.png?alt=media" alt=""><figcaption><p>Location of the explosion IFX object bubble</p></figcaption></figure>