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Working with Hardie® products – Silica IS an issue

This month I would like to focus on safe practices of a particular product which seems to be very popular for Habitat home exteriors, Hardie Plank siding. I have installed more Hardie siding than I care to think about. However, I have not always worked with the product in the safest way.

Below are some of the dos and don’ts directly from Hardie. Please read them and you may find some ways to increase your safety and those of your co-workers when install Hardie siding. Managing Silica Exposures James Hardie® believes that safety should be of paramount importance to everyone and is committed to the safe use of its products.

James Hardie has established the following Recommended Cutting Practices as an easy-to-follow, practical guide to help you reduce the risk of potential silica exposures.


  1. Position cutting station so that wind will blow dust away from user and others in working area.
  2. Use one of the following methods:
    • Best:
      • Score and snap for 3 x 5 Hardie panels
      • Shears (Pneumatic or Handheld) for Hardie Siding
    • Better:
      • Dust reducing circular saw equipped with a HardieBlade® saw blade and HEPA vacuum extraction
    • Good:
      • Dust reducing circular saw with a HardieBlade saw blade (only use for low to moderate cutting)


  1. Cut only using score and snap, or shears (manual, electric or pneumatic).
  2. Position cutting station in well-ventilated area
    • NEVER use a power saw indoors
    • NEVER use a circular saw blade that does not carry the HardieBlade saw blade trademark
    • NEVER dry sweep. Use wet suppression or HEPA Vacuum

Important Note: For maximum protection (lowest respirable dust production), James Hardie recommends always using “Best”-level cutting methods where feasible.

James Hardie encourages you to always minimize all dust exposures. As such, properly-fitted NIOSH approved respirators (e.g. N-95) can be used in conjunction with Recommended Cutting Instructions to provide additional protection against silica exposures. NOTE: Prior to use, follow the respirator manufacturer’s use instructions and comply with all applicable government regulations.

Cutting using the score and snap method (3 x 5 Panels)
By using a straight-edge as a guide, score with carbide tipped scoring knife. Snap the sheet upwards toward the scored line.

Cutting with shears (Hardie Siding)
For smoother edges, always cut from the back of the product with the top two blades of shear flush against the board.

Reducing dust exposures with a dust-reducing circular saw
You should set-up cutting station in well-ventilated, outdoor area with wind blowing dust away from user and others in area. It is strongly recommended that a dust-reducing saw be connected to a HEPA vacuum to further reduce respirable dust exposures.  NEVER use a high speed power tool in a poorly ventilated or covered area such as a garage, patio, or carport.

Diablo® HardieBlade™
With only four poly-crystalline diamond teeth, the Diablo® HardieBlade™ by Freud Tools will produce less respirable dust as compared to a traditional framing or masonary blade when cutting fiber cement products. James Hardie® recommends that only the HardieBlade be used.

  • NEVER use a continuous Rim Diamond Blades (or segmented masonry blades) as they can create unsafe dust levels when cutting fiber cement products.
  • NEVER use a grinder to cut as it may generate unhealthy dust levels.

James Hardie® products contain respirable crystalline silica, which is known to the State of California to cause cancer

  • It is considered by IARC and NIOSH to be a cause of cancer from some occupational sources.
  • Breathing excessive amounts of respirable silica dust can also cause a disabling and potentially fatal lung disease called silicosis, and has been linked with other diseases.
  • Some studies suggest smoking may increase these risks.

During installation or handling:

  1. Work in outdoor areas with ample ventilation.
  2. Use fiber cement shears for cutting or, where not feasible, use a HardieBlade® saw blade and dust-reducing circular saw attached to a HEPA vacuum.
  3. Warn others in the immediate area.
  4. Wear a properly-fitted, NIOSH-approved dust mask or respirator (e.g. N-95) in accordance with applicable government regulations and manufacturer instructions to further limit respirable silica exposures.

During clean-up:

  1. Use HEPA vacuums or wet cleanup methods - never dry sweep.

For further information, refer to our installation instructions and Material Safety Data Sheet available at or by calling 1-800-9HARDIE (1-800-942-7343).


Copyright 2012 James Hardie Building Products, Inc.

Keep safe,
Frank Peccia, Safety officer