Managing blast fumes

Blast fumes are gases that may be generated during blasting. These can include nitric oxide and nitrogen dioxide, both of which can seriously affect people's health, so it is vital to manage them.

Characteristics of blast fumes

Blast fumes can be a reddish/orange cloud, which shows the presence of nitrogen dioxide (NO2). This colour is more pronounced and deeper with higher NO2 concentrations.

Blast fumes with NO2 also have a pungent odour and taste. NO2 has a very strong acrid odour that can be smelled at much lower levels than the tolerable limits. At low levels, the effects are extremely unlikely to be harmful to health, particularly if you can't see the reddish/brown gas.

NO2 above 2.5 parts-per-million (ppm) is visible. Concentrations above 4ppm may deaden the sense of smell.

Tolerable exposure

There is a level of tolerable exposure that people can deal with. The short-term exposure limit (STEL) for NO2 is 5ppm. STEL exposures should not last longer than 15 minutes and not be repeated more than 4 times a day with at least 60 minutes between successive exposures.

Mine sites should work towards preventing fume generation. However, where this isn't possible, they should keep fume exposures below the STEL.

Symptoms of overexposure

  • Eye irritation and coughing
  • Initial dizziness and/or headache (may subside)
  • Shortness of breath
  • Cyanosis (blue lips, fingertips) 5–8 hours later

Responding to exposure

Immediately report exposure to your supervisor and follow the site medical plan. If a medical practitioner examines and releases you but you develop symptoms later, seek urgent medical attention.

Preventing exposure to blast fumes

  • Set and maintain credible blast-exclusion zones and fume-management zones.
  • Inform blast controller of fume clouds, and their location and movement.
  • Do not enter or remain in fume clouds.
  • Move out of fume cloud path.
  • Wear gas monitors if directed.

You can measure NOx using portable gas detectors. Calibrate and set monitors correctly before use.

Contact