Oxidizing Substance Warning Sign W028 | ISO 7010

Oxidizing Substance Warning Sign - ISO 7010 W028

Warn personnel about oxidizing substances with this ISO 7010 W028 compliant warning sign. The sign displays the standardised yellow triangle with black border and the black flame over circle pictogram, internationally recognised as the warning for oxidizing materials.

What does the W028 sign mean?

The W028 symbol warns that oxidizing substances are present, stored or handled in the area. Oxidizers are not necessarily flammable themselves, but they release oxygen and can cause or dramatically intensify fires in contact with combustible materials. Typical examples include hydrogen peroxide, chlorates, perchlorates, nitrates, permanganates and pool chlorine chemicals.

Where to install this sign

Install W028 warning signs at chemical storage rooms, laboratories, water treatment plants, swimming pool plant rooms, fertiliser warehouses, oxygen system installations, and any area where oxidizing agents are stored or processed. Position at eye level at access points and directly at the storage location.

W028 workplace sign vs GHS packaging pictogram

The ISO 7010 W028 sign (yellow triangle) marks workplace areas where oxidizers are present. It should not be confused with the GHS03 pictogram (red-bordered diamond with flame over circle), which appears on the packaging labels of individual containers under CLP regulation. A compliant facility typically needs both: GHS labels on containers and ISO 7010 area signage on walls and doors.

Materials and sizes

Available in rigid PVC (1 mm), aluminium and photoluminescent versions, in multiple sizes to match your viewing distance. All materials are UV-stable and suitable for indoor and outdoor use.

Frequently asked questions

Is the W028 sign mandatory? European workplace safety regulations (Directive 92/58/EEC) require appropriate warning signage wherever hazards cannot be eliminated. If oxidizing substances are stored or handled, area warning signage is required.

Which size should I choose? As a rule of thumb, the sign area in cm² should be at least the square of the viewing distance in metres divided by 2000. For a 10 m viewing distance, choose at least a 200x200 mm sign.

What is the difference between W028 and W021? W021 warns of flammable materials (flame symbol), while W028 warns of oxidizing substances (flame over circle). Oxidizers feed fires with oxygen rather than burning as fuel.