This article was posted on Friday, Jun 01, 2018

The authors spoke at our January members’ meeting on the importance of familiarizing ourselves with the serious issue of mold and lead. Here’s a summary of their presentation. 


Mold is fungus, and mold spores are present outside and inside of our homes every day. This is normal. In fact, many molds are beneficial, such as the one that produces the antibiotic Penicillin. In some people, however, mold can trigger allergic reactions, worsen asthma, and in rare cases, cause fungal infections.

Mold grows where food, moisture, and the right temperature combine. Food for mold includes building materials such as sheetrock and paint. The moisture sources are water intrusion in our homes and our daily living activities: breathing, bathing, cooking, etc. A cold unit causes the warm moisture in the indoor air to condense on the cold interior building surfaces that serve as food, thereby producing mold growth. 

Advice to Tenants: How to Prevent Mold Growth

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  • Ventilate the unit every day.
  • Wipe down condensation on windows, shower walls.
  • Keep furniture six inches away from exterior walls to
  • prevent trapping moisture.
  • Notify property owner of leaks, ventilation problems 

Advice to Property Owners for Managing Mold

  • Don’t bother testing (sampling) for mold. If you or a tenant smell mold, but on inspection, you find no visible evidence of it, you may need to look behind the walls, baseboards, carpeting, or ceilings.
  • Locate moisture sources and eliminate them. Trapped moisture will cause mold growth, including growth into sheetrock or plaster, with negative health effects and legal liability for the owner. Mold also causes dry rot and other structural damage to the building, necessitating costly repairs and disruption.
  • Don’t paint over mold; clean it off, if possible. Mold has fine root-like strands. With enough time and moisture, the mold grows into the sheetrock/plaster or wood itself, making it impossible to remove by simple cleaning. When that happens, the affected material must be removed and replaced. For more information, check the California Department of Public Health factsheet Mold or Moisture in My Home:What Do I Do? at:

  • Maintain your building so that moisture does not accumulate. Promptly repair heaters, drafty or leaky windows and doors, or windows that won’t open, and keep an eye out for signs of water intrusion.
  • While looking for leaks or repairing moist building materials, the paint on these materials may be disturbed, creating lead hazards. 


Lead-based paint materials and lead-contaminated yard soil from decades of leaded gasoline use are the two primary sources of lead poisoning in San Francisco.

Until 1978, when it was finally banned, leaded paint was the standard on nearly all building interiors and exteriors. The lead in old paint peeling from the City’s many poorly-maintained old buildings and the scrapings and fine particles from unprofessional old paint stripping put the lead in the air and in the soil.

Both adults and children can be lead-poisoned, but young children are most vulnerable and can suffer permanent effects to brain and nervous system development. In adults, long-term health effects may include high blood pressure, kidney damage, decreased fertility, and birth defects in newborns. Very young children can become lead-poisoned because they have a tendency to put things in their mouths.

It’s important to note that lead in painted walls and yard soil is not an issue as long as the lead-containing painted surfaces are intact and undisturbed, and the soil is covered and not accessible to young children. 

Make Sure Your Property Has No Lead Hazards

  • Look for signs of surface deterioration (peeling paint, open cracks) and repair promptly.
  • Cover bare soil.
  • If having your pre-1978 building painted, make sure your contractor is trained and qualified to work safely with lead paint, and follows the SF Housing Code. Unless ALL the old paint has been stripped from the building, it will still contain lead-based paint and have a potential lead hazard.


David Lo and Karen Yu are with the, Children’s Environmental Health Promotion Program, San Francisco Department of Public Health. Reprinted with permission of the Small Property Owners of San Francisco Institute (SPOSFI) News.  For more information on becoming a member of SPOSFI or to send a tax-deductible donation, please visit their website at or call (415) 647-2419.