Most elements in this category all burn or react when exposed to FIRE (except FIRE itself, C5 and CFLM), and each element has different properties that cause it to react differently. Pressure, high temperature (temp), electricity, contact with other particles, fire (FIRE), plasma (PLSM), and even water (WATR) can be triggers to certain elements in this category.

Fire

Description: "Ignites flammable materials. Heats empty space around it with the Ambient heat setting on."

Type: Gas (considered a powder for some walls)

Ignites flammable substances and heats up most elements. When FIRE is hot enough, it turns to Element:PLSM.

Gunpowder

Description: "Gunpowder. Light dust, explodes on contact with FIRE or spark (SPRK)."

Type: Powder

Explosive powder.Can be ignited by SPRK, FIRE, or a temp of 400C or greater.

Nitroglycerin

Description: "Nitroglycerin. Pressure sensitive explosive. Mix with CLST to make TNT."

Type: Liquid.

Spawn temp: +22.00 C / 295.15 K.

Hex triplet colour: #20e010.

Flammable; explosively ignites if in contact with SPRK, FIRE, PLSM, or LAVA.

Forms TNT if mixed with CLST.

Transforms to OIL if irradiated with NEUT.

C-4

Description: "Solid pressure sensitive explosive."

Type: Solid

Will explode when exposed to high pressure, SPRK, heat, or FIRE. Transforms into GOO when exposed to NEUT.

Rubidium

Description: "Rubidium. Explosive, especially on contact with water. Low melting point."

Type: Solid

Explodes on contact with WATR, ACID and FIRE. Will not explode with SPRK, unlike other explosives. It will instead conduct just like normal metal. Melts into liquid rubidium at ~37.8C.

Liquid Rubidium

Description: "Liquid Rubidium."

Type: Liquid

The same as RBDM, except it's a liquid.

Thunder

Description: "Lightning! Very hot, inflicts damage upon most materials, transfers current to metals."

Type: Powder

Very hot liquid-like substance, passes a SPRK to any conductive materials. One of the most destructive elements, will create a strong pressure shock wave (256 pressure) as well as conducting its temp when in contact with non-metals (or metals that are unable to conduct electricity because a spark has just passed by). THDR's movements are not affected by pressure.

Thermite

Description: "Thermite. Burns at extremely high temperature."

Type: Powder

THRM will react with FIRE, PLSM, LAVA and LIFE. It generates very large amounts of heat (Around 3000C just after ignition), hot enough to melt TTAN. Molten THRM turns into BMTL when cooled.

Cold flame

Description: "Sub-zero flame."

Type: Gas

'Cold Fire' that burns at -273.15C/0K. Will ignite C-5 and ANAR, but not other elements.

Fireworks

Description: "Fireworks! Colorful, set off by fire."

Type: Powder

After contacting FIRE, FIRW will shoot off upward and explode with hot (temp of 6000C to 9000C) and colorful embers. Use decorations to change ember colors.

Explodes when tmp > 1, and life = 0.

Lightning

Description: "Lightning. Change the brush size to set the size of the lightning."

Type: None / Special

Bolt or "Arc" Lightning, Very short-lived element, ~2 to 5 frames of persistence. Upon clicking a "bolt" of LIGH will extend from the brush (angle is random, always downward when with the gravity setting on 'vertical', but at any angle when the gravity setting is 'off' (and generally pointing toward the centre of the screen when the gravity setting is on 'radial')), then dissipate, leaving a "thunderclap" pressure wave in its wake. Generates an extreme amount of heat and pressure upon making contact with another element, but not penetrating it, striking the surface only. Will spark conductors that survive the impact. Can be produced by sparking TESC. Length, temp, and pressure of bolt are based on the brush size used to produce it.

Destructive

Description: "More destructive Bomb, can break through virtually anything."

Type: Powder

Much more destructive than BOMB. When within 2 pixels of another element (except for DMND, any type of clone, or any type of Wall), DEST releases high amounts of heat and pressure, melting and/or scattering most elements. DEST survives for many frames after the initial impact and often tends to dig into whatever is in the way.

Old Fireworks

Description: "Original version of fireworks, activated by heat/neutrons."

Type: Powder

Explodes with neutrons or heat (200C). Jumps higher than FIRW but has odd trajectories and pale embers. Explodes when hot (temp of ~7000C upwards).

Bomb

Description: "Bomb. Explodes and destroys all surrounding particles when it touches something."

Type: Powder

Explodes when it touches any other particles except for DMND, any type of clone, or any type of Wall. When BOMB explodes, all particles within an 8 pixel radius are replaced by EMBR (except for diamond, clone, etc) at 9725.85C, with pressure produced. This EMBR 'shrapnel' is ejected at the explosion temperature after explosion occurs, causing damage. However, the shrapnel's conductivity rapidly decreases with its life and will cease to exist after a while.

C-5

Description: "Cold explosive, set off by anything cold."

Type: Solid

Explodes when cold, produces CFLM and pressure. Only reacts with LOXY, LN2, CFLM, TRON and any other liquid cooled to below -173.85C/99K. Not pressure sensitive, and does not explode when sparked.

TNT

Description: "TNT, explodes all at once"

Type: Solid

A solid explosive similar to C-4, but creates more pressure and less fire. It is quite a hot explosive, hot enough to melt METL. TNT will explode into bomb shrapnel upon detonation. TNT is the only explosive that explodes instantaneously upon ignition. It was added in version 69.0 beta.

Ignition Cord

Description: "Ignition cord. Burns slowly with fire and sparks."

Type: Solid

A slow burning fuse-like material. IGNC, unlike FUSE, can be ignited by FIRE as well as hot materials. It burns with EMBR and FIRE at low temperatures. IGNC can be used as a delay to set off low grade explosives, and it can also burn in WATER. NEUT can pass through IGNC without distortion. Added in v70.0.

Fuse

Description: "Burns slowly. Ignites at somewhat high temperatures or with electricity."

Type: Solid

When its temp is above 700 degrees or it is sparked, it slowly turns into PLSM. Breaks into FSEP at >2.7 pressure (with a slight delay)

Fuse Powder

Description: "Fuse Powder. Burns slowly like FUSE."

Type: Powder

Powdered FUSE, works in the same way (burns into PLSM with high temperature or electricity)

Lithium

Description: "Lithium. Reactive element that explodes on contact with water."

Type: Powder

It absorbs CO2 and then can be converted to GLAS. On contact with water it will heat itself by and turn water into hydrogen. At 1000K it explodes. When pure it can be used to make batteries.

This tutorial save demonstrates the above reactions in game.