Print this page Print this page

Mold Remediation in the Workplace-OSHA Guide

John Poullain, P.E.

Course Outline

This three-hour online course provides guidelines for the procedures and measures taken for the mold remediation of offices and commercial buildings. The topics covered in the text include the causes of indoor mold problems, sources and types of mold, guidelines for cleanup of buildings having or not having mold growth and how to determine if the mold remediation and cleanup has been finished successfully. The course presents methods and recommendations to identify and measure sources of mold; mold growth related health effects, ways to reduce exposure and methods for mold prevention. The course covers several links and references to informative sources and resources covered in the text topics.

This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.

Learning Objective

At the conclusion of this course, the student will:

Intended Audience

This course is intended for building managers, mold remediators and IAQ professionals.

Benefit to Attendees

The student will become familiar with the causes of mold, health risks, which people are more susceptible and suitable actions to take for indoor mold problems. Information is provided on how mold problems are identified and pollution levels are evaluated. The basic methods for improving indoor air by controlling the sources of water, moisture and ventilation are discussed. The student will consider the principles of mold sampling and requirements for taking samples. Reference sources are provided for additional information pertaining to indoor air problems, health effects linked to the molds and appropriate steps for reducing the exposure to occupants and remediators.

Course Introduction

Molds can be found anywhere and are important for breaking down matter. When found indoor mold presents health problems to the occupants and cause destruction of building materials, building structures and furnishings. The text for this course was prepared by the Occupational Safety & Health Administration (OSHA) as a guide to assist building professionals, building managers and others interested in improving building air quality. Many organizations, governmental and private industry, have published documents for guidance in mold remediation, including the USEPA, NYC Dept of Health, Texas Dept of Health and Health Canada. It should be noted that for mold remediation to succeed not only must visible mold be removed but any moisture problems, which promote mold growth, must also be corrected. Hidden mold must also be considered. The goal of the course is to understand the causes of mold growth and the effects on indoor air quality of buildings. The recommended methods used to reduce adverse health problems that affect the welfare and performance of the building occupants are discussed.

The OSHA guide has recommendations for remediation containment which range from none (Level I) to complete isolation of work areas from adjacent occupied spaces. For Levels I, II and III dust suppression is recommended and for Level VI full containment. OSHA and the US EPA designate remediation work areas by size as follows:

OSHA US EPA Size of Area
Level I Small 10 sq. ft. or less
Level II ---- 10-30 sq. ft.
Level III ---- 30-100 sq. ft.
-------- Medium 10-100 sq. ft
Level IV Large 100 sq. ft. and greater

It has been estimated that people spend as much as 90% of their time indoors at home, office, schools, stores or other commercial buildings. This has become a serious health problem since indoor air quality may be poorer than outdoor air quality. Some people including the young, elderly, those afflicted with respiratory diseases and those with reduced immunity systems are especially susceptible to indoor mold. OSHA estimated 30% of Americans work in buildings, which have some type of air pollution. Asthma attacks are often triggered by mold or mold-laden dust and estimated as the forth-leading cause of work absenteeism.

Concern over indoor air quality (IAQ) has generated the sale of air cleaning and purification devises, carbon monoxide detectors, electrostatic filters, ultraviolet germicidal irradiation devises and radon test kits as a means to protect occupants or detect indoor air pollutants. Outside air supply systems are used in buildings with HVAC systems to provide the ASHRAE standards for rates of air exchange. Some gas-phase air filtration systems permit a reduction in outside air supply to cut costs. The statistics for people affected by allergies, asthma and other respiratory diseases have been increasing for all age groups. Building managers have become aware of the negative effect of an uncomfortable or harmful building environment. Poor indoor air can also impair students' learning ability. Prominent factors of poor IAQ, tobacco smoke and sick building syndrome have received much public attention causing regulatory actions and litigation has pushed building owners to monitor and improve indoor air quality. Mold also is perceived to cause serious harm and long term health problems and perhaps may be "the next asbestos". Just a few years ago some yellow pages had no listings for mold remediation and cleanup.

Sources of mold affecting indoor air quality include:

1. HVAC problems:

a. Inadequate HVAC and filtration and outdoor air supply equipment that do not maintain relative humidity in the ideal 30-60% range and/or keep the inside surface temperatures above the dew temperatures.

b. Mold contaminated HVAC and air handler equipment, air ducts and air diffusers.

2. Water sources: leaks from pipes, fountains, restrooms, leaks through exterior walls, roofs, cracks in walls and water in drip pans and water spills.

3. Moisture sources: exhalation of occupants, unvented showers and dryers, humidifiers, outside air supply, wet foundations, poorly insulated ceilings, condensation on wall surfaces, room surfaces or within wall cavities.

4. Infiltration of outdoor mold spores or from mechanical ventilation using outdoor air supply.

There are many regulations for air quality but most pertain to outdoor air quality and the emission of pollutants into the atmosphere. Until now indoor air quality standards could not be easily developed because there were no monitoring devises available to take accurate measurements. Indoor air quality is a complex problem which is hard to target because of ever changing types and levels of pollution and the occupant's susceptibility and perception of indoor conditions. Factors affecting indoor air are mold sources, operation and maintenance of ventilation systems, moisture and humidity control. Because air and surface cleaning alone cannot remove all indoor mold and mold spores are most effectively controlled by the following regime of activities:

1. Effective source control. Manage the sources of mold growth by removal or control of moisture or water problems.
2. Adequate ventilation and moisture control. Ventilate the building with adequate ventilation or rates of air exchange.
3. Air filtration. Clean the air and remove mold spores with adequate filtration equipment and filters recommended by ASHRAE.


Course Content

This course is based primarily on the Occupational, Safety and Health Administration guide, "A Brief Guide to Mold in the Workplace", SHIB 03-10-10 (2003 Edition, 10 pages), PDF file. The course is also based on the National Center for Environmental Health publication, "Molds on the Environment", CDC publication (2006 Edition, 4 pages), PDF file.

The links to the course materials are:

A Brief Guide to Mold in the Workplace

Molds in the Environment

You need to open or download above documents to study this course.

Course Summary

This course considers the mold sources, health risks and actions to take to improve indoor air quality with mold remediation/cleanup in buildings and the workplace. It presents the methods and actions to take if indoor mold is a problem or you suspect it may have affected the health of the building occupants. Mold sampling, when it is felt necessary, types of samples and requirements are considered. Informative reference lists for indoor mold is provided for the sources, effects on health, available resources and necessary steps to control and reduce exposure.

Related Links

For additional technical information related to this subject, please refer to:
The site provides an introduction to health and IAQ, sick building syndrome causes, diagnostic quick reference and diagnostic checklists to target the most likely building pollution problems. Information and reference material about IAQ improvement and point source controls are presented.
IAQ topics for buildings, schools, home, FAQ, information and guidance for air quality regulations.
IAQ for large buildings using I-BEAM developed by the EPA for building professionals and other in IAQ for commercial buildings. Guidance with module presentation for IAQ problems and how to solve them.


Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.

DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.