Definition: Hazardous materials refer to any substance defined or identified by any governmental authority as harmful to the environment or capable of posing a risk of injury to public health and safety. The term includes, without limitation, any substance, whether in the form of a solid, liquid, gas or any other form whatsoever, which requires special handling in its use, transportation, generation, collection, storage, treatment or disposal. These materials include but are not limited to: liquid chemicals, dry chemicals, gases, asbestos, lead base paint, sewage, mold, and biological hazards. Hazardous substances may enter your body in three ways: ingestion, inhalation, and absorption through the skin.

Before you authorize any demolition, repair, or remodeling, have a hazardous material site survey performed by a state certified environmental testing laboratory to determine what, if any, materials in or around the building contain hazardous materials. If hazardous materials are found, they should be removed and disposed of by a certified and licensed hazardous material abatement contractor before any repair work begins.


  • Gardening Chemicals (pesticides, herbicides, fertilizers, etc.)
  • Automotive Chemicals (solvents, oils, anti freeze, brake fluid, gasoline, diesel fuel, battery acid, etc.)
  • Pool Chemicals (chlorine, bromine, hydrochloric acid, sodium hypochlorite, etc.)
  • Household Chemicals (bleach, ammonia, detergents, drain cleaner, paint thinner, turpentine, mineral spirits, adhesives, kerosene, lighter fluid, aerosol cans, medications, etc.)

If certain chemicals are spilled and mixed with other chemicals, toxic fumes, explosive gases, and/or combustion into fire can result. A chemical spill can also saturate and contaminate anything it comes in contact with, including drywall, wood, soil, and concrete surfaces. Even breathing residual odors or fumes can be lethal. If you see any unknown spilled substances or liquids and/or smell any unusual odor, leave the area immediately and contact the fire Department. Federal, state, and local governing agencies have strict regulations in place that govern the proper clean up and disposal of hazardous materials and chemicals. Do not attempt to clean up spilled chemicals or hazardous materials or dispose of them yourself. Contact the professionals first and let them handle it!

Hazardous materials warning labels


Asbestos warning label

Asbestos occurs naturally in the environment around the world. California's state rock consists of one type of asbestos fiber called chrysotile. Asbestos refers to several varieties of mineral fibers that are mined and processed for commercial uses around the world. By the 1970s, asbestos had become an integral component of approximately 3,600 commercial products and was used extensively in the United States from the early 1900's until the late 1970's and was used in insulation products and for providing fire resistance to buildings. After the late 1970's, asbestos became widely recognized as a serious health hazard and was no longer permitted to be used in most building materials. However, many material suppliers had huge stock piles of materials that contained asbestos that were allowed to be used and or sold to the public until those supplies were exhausted. For this reason, asbestos containing materials can still be found in buildings built after 1985.

Asbestos is Commonly Found in:

  • Roofing materials
  • Flooring
  • Interior plaster
  • Exterior stucco
  • Pipes & pipe insulation
  • Ceiling tiles & insulation
  • Furnaces and air ducts
  • Inside fuse boxes
  • Electrical wiring jackets
  • Boilers, transite vent piping
  • Siding
  • Old vinyl floor tiles & mastic
  • Sprayed on acoustic (popcorn ceilings)
  • Drywall taping mud and patching compounds
  • Textured paints
  • Artificial ashes and ambers sold for use in gas-fired fireplaces
  • Gunnite/sprayed on fire-proofing

All forms of asbestos fibers can cause cancer and are classified as known human carcinogens by the Environmental Protection Agency (EPA). Once asbestos containing materials are disturbed during remodeling or demolition, the fibers can become airborne. It can take 15-40 years after exposure to asbestos for cancer or respiratory diseases to develop.

Asbestos presence house diagram

Inhaling Asbestos Fibers Can Cause the Following Diseases:

  • Asbestosis: A serious, chronic, non-cancerous lung disease. The disease is usually disabling and can be fatal
  • Mesothelioma: A rare cancer affecting thin membranes lining the lungs. This type of cancer is always fatal
  • Lung Cancer

What is Friable Asbestos-Containing Material?

Friable asbestos containing material (ACM) is any material containing more than 1 % asbestos, determined by Polarized Light Microscopy that, when dry, may be crumbled, pulverized, or reduced to powder by hand pressure.

Category 1 non-friable ACM are asbestos-containing resilient floor coverings, commonly known as vinyl asbestos tile or VAT, asphalt roofing products, packings, and gaskets. All other non-friable ACM are generally considered Category 11 non-friable.

If you sand, grind, abrade (scrape), drill, and cut or chip any non-friable materials, including Category I materials, you have now turned it into friable material and must treat the material as friable, if more than the jurisdictional amount is involved.

For more information on asbestos, visit the U.S. Environmental Protection Agency website here. For a complete list of materials that may contain asbestos, visit here or the Mesothelioma Center here.

Many houses, apartments, and commercial buildings built before 1978 have paint that contains high levels of lead. This type of paint is commonly referred to as Lead Based Paint (LBP). Lead from paint, chips, and dust can pose serious health hazards if not taken care of properly. By law, any building (other than schools) built prior to 1978, that has painted surfaces, MUST be handled as LBP unless a certified inspector has determined such surfaces to be below the regulated limits.

It's the Law!

Federal law requires that contractors who disturb lead-based paint in homes, childcare facilities and schools, built before 1978 to be certified and follow specific work practices to prevent lead contamination. Ask to see your contractor's certification. To obtain a printable copy of Renovate Right - Important Lead Hazard Information for Families, Child Care Providers and Schools, visit the EPA website here.

Lead exposure can harm young children and babies even before they are born. People can get lead in their bodies by breathing or swallowing lead dust, or by eating soil or paint chips containing lead. Improper removal of lead-based paint can expose your family and others to a hazardous risk.

In children, lead can cause:

  • Nervous system and kidney damage
  • Learning disabilities
  • Speech, language, and behavior problems
  • Poor muscle coordination
  • Decreased muscle and bone growth
  • Hearing damage

In adults. Lead can cause:

  • Increased chance of illness during pregnancy
  • Harm to fetus
  • Fertility problems
  • High blood pressure
  • Digestive problems
  • Nerve disorders
  • Memory and concentration problems
  • Muscle and joint pain

Deteriorating lead-based paint (peeling, chipping, chalking, cracking or damaged) is a hazard and needs immediate attention. Take precautions before your contractor or you begin remodeling or renovating anything that disturbs painted surfaces:

  • Have the area tested for lead-based paint
  • Do not use a belt-sander, propane torch, or high temperature heat gun, dry scraper or dry sandpaper
  • If you can't move your family, at least completely seal off the work area

For more information regarding the hazards of lead, visit the EPA website here.

Radioactive Material

Radioactive material warning

The following information was obtained from FEMA's book "Are You Ready" and can be viewed here.

Nearly 3 million Americans live within 10 miles of an operating nuclear power plant.

Although the construction and operation of these facilities are closely monitored and regulated by the Nuclear Regulatory Commission (NRC), accidents are possible. An accident could result in dangerous levels of radiation that could affect the health and safety of the public living near the nuclear power plant.

Local and state governments, federal agencies, and the electric utilities have emergency response plans in the event of a nuclear power plant incident. The plans define two "emergency planning zones." One zone covers an area within a 10-mile radius of the plant, where it is possible that people could be harmed by direct radiation exposure. The second zone covers a broader area, usually up to a 50-mile radius from the plant, where radioactive materials could contaminate water supplies, food crops, and livestock.

The potential danger from an accident at a nuclear power plant is exposure to radiation. This exposure could come from the release of radioactive material from the plant into the environment, usually characterized by a plume (cloud-like formation) of radioactive gases and particles. The major hazards to people in the vicinity of the plume are radiation exposure to the body from the cloud and particles deposited on the ground, inhalation of radioactive materials, and ingestion of radioactive materials.

The longer a person is exposed to radiation, the greater the effect. A high exposure to radiation can cause serious illness or death.

Although the risk of a nuclear accident is slight, knowing how to react during an emergency can reduce the risk of injury.

Minimizing Exposure to Radiation

There are three main factors to minimize exposure to radiation. These include:

  • Time - Most radioactivity loses its strength fairly quickly
  • Distance - The more distance between you and the source of the radiation, the better. This could be evacuation or remaining indoors to minimize exposure
  • Shielding - The more heavy, dense material between you and the source of the radiation, the better

While there are no nuclear power plants located in San Mateo County, if an accident at a nuclear power plant were to release radiation in your area, local authorities would activate warning sirens or another approved alert method (i.e., SMC Alert). They also would instruct you through the Emergency Alert System (EAS) on local television and radio stations on how to protect yourself. Follow the instructions you receive from this station. Your instructions may include directions for evacuating or for remaining where you are (called sheltering in place) to reduce any possible exposure to radiation.

Take Protective Measures

During a Nuclear Power Plant Emergency

The following are guidelines for what you should do if a nuclear power plant emergency occurs. Keep a battery-powered radio with you at all times and listen to the radio for specific instructions. Close and lock doors and windows.

If you are told to evacuate:

  • Keep car windows and vents closed; use recirculating air

If you are advised to remain indoors:

  • Turn off the air conditioner, ventilation fans, furnace, and other air intakes
  • Go to a basement or other underground area, if possible
  • Do not use the telephone unless absolutely necessary

If you are told to evacuate:

  • Keep car windows and vents closed; use re-circulating air

If you expect you have been exposed to nuclear radiation:

  • Change clothes and shoes
  • Put exposed clothing in a plastic bag
  • Seal the bag and place it out of the way
  • Take a thorough shower

Keep food in covered containers or in the refrigerator. Food not previously covered should be washed before being put into containers.

Seek medical treatment for any unusual symptoms, such as nausea, that may be related to radiation exposure.

The following information was provided by the United States Nuclear Regulatory Commission and can be viewed here.

Use of Potassium Iodide

In January 2001, the Commission published a rule change to the NRC emergency planning regulations to include the consideration of the use of potassium iodide. If taken properly, potassium iodide (Kl) will help reduce the dose of radiation to the thyroid gland from radioactive iodines and reduce the risk of thyroid cancer. The Food and Drug Administration (FDA) has issued guidance on the dosage and effectiveness of potassium iodide, which can be viewed here.

The NRC has supplied Kl tablets to States requesting it for the population within the 10-mile emergency planning zone (EPZ). If necessary, Kl is to be used to supplement evacuation or sheltering in place, not to take the place of these actions. If radioactive iodine is taken into the body after consumption of potassium iodide, it will be rapidly excreted from the body. For more information, see Consideration of Potassium Iodide in Emergency Planning here.

NOTE: Potassium iodide will not protect you from the effects of radiation, it will only keep your thyroid from absorbing radioactive iodine.

Remember, in the unlikely event of a nuclear power plant accident, it is important to follow the direction of your State or local government in order to make sure protective actions, such as taking potassium iodide pills, are implemented safely and effectively for the affected population.

For more information on radiation or radioactive material concerns, visit the United States Nuclear Regulatory Commission website here or review FEMA's book "Are You Ready" here.

Hazardous material labels and warnings