Asbestos is a group of naturally-occurring silicate minerals, known for their resistance to heat, electrical and chemical damage, sound absorption and tensile strength. It's used in building construction for its flame retardant and insulating properties.

Inhalation of asbestos fibers can cause serious illnesses that are strongly associated with exposure to asbestos. Airborne asbestos fibers are a significant health threat because asbestos fibers are microscopic and invisible to the unaided eye. In addition, they have the physical characteristics to bypass the ability of the human lung to filter air contaminants. As a result, exposure to asbestos allow the fibers to reach deep within the lungs, and may irritate and scar lung tissues. Long-term chronic and acute exposure to asbestos fibers may cause respiratory diseases such as lung cancer, asbestosis and mesothelioma.

Asbestos containing materials become a health hazard once they are disturbed. Intact, asbestos fibers embedded within construction materials and components are inert and do not pose a health hazard; however, once they are disturbed, through physical contact or building renovation and demolition activities, asbestos fibers may be rendered airborne.

The informational website from AQMD contains information about work practice requirements when demolition may release asbestos.

Generally, it involves the following:

• Survey: the presence of asbestos will be determined before any demolition or renovation activity
• Notification: LADBS will be notified that renovation activity involving asbestos will be conducted. An on-site representative must be present.
• Warning labels must be displayed on site and during transportation
• Removal Procedures:
• Stationary objects not involved in demolition will be covered with plastic sheeting,
• Doors, windows, vents, and registers in the work area will be rendered airtight using plastic sheeting or studded wood barriers.
• All sources of air movement will be shut off.
• Work area vented with an intact HEPA filter.
• Any material possibly containing asbestos will be wet down during cutting or dismantling.