The United States experienced several large hurricanes over the past few years, resulting in loss of life and billions of dollars in property damage. Hurricane force winds damaged roofs, building envelopes, and electrical power distribution systems. Overwhelmed and obstructed public drainage systems allowed falling rainwater to accumulate and flood the lower levels of residential and commercial facilities. For most of these hurricane events, the rapid moisture intrusion, combined with the inability to remove and/or dehumidify the water-damaged building materials, resulted in odors and visible mold inside of wall cavities, on building interior surfaces, and on contents. Some of these damaged facilities were addressed promptly and properly, however many were not. This edition of HETI Horizons discusses the residual effect on indoor air quality (IAQ) that may occur when insufficient remediation efforts are conducted to address large water intrusion events.
Initial Response
After the hurricanes were over, most facilities conducted assessments to identify storm-related losses. Property damage often included roofs, heating ventilation and air conditioning (HVAC) systems, windows, flooring, and wall coverings. The Environmental Protection Agency (EPA) recommends that standing water be removed and interior building components dried out within 24-48 hours to limit potential mold growth. Unfortunately, with limited electrical power and personnel resources, appropriate response to the damaged facilities was difficult. Electrical power restoration times ranged from days to several weeks for water-damaged facilities within the continental U.S.. And Hurricane Maria left approximately 121,000 residents of
Puerto Rico without power for more than six months!
While waiting for restoration of electrical power, some companies removed and discarded moisture-impacted porous floor coverings (carpet) and porous wall coverings (drywall) from the facilities. However, many facilities, due to lack of personnel and
financial resources, were unable to remove these water-damaged materials – resulting in mold growth on building interior surfaces and furnishings, behind baseboards and wallpaper, and within ceiling and wall cavities.
With the restoration of electrical power, businesses, hospitals and schools were eager to return to normal operations as quickly as possible. HVAC systems were turned back on and the facilities were dried out as best as possible; but the shortage of industrial dehumidifiers and fans prohibited a rapid dry-out of the buildings. Many facilities did not have experienced internal personnel, or were unable to retain environmental professionals to validate that the building materials’ moisture contents were within acceptable ranges.
For several facilities, the removal of mold- and bacteria-impacted walls, floor coverings, and furnishings was not conducted. Instead, the carpets were cleaned and the walls painted. Any residual odor from the water- or mold-damaged materials was initially masked by the scents of the cleaning chemicals, deodorizers and fresh paint. Typically, the purpose of these limited facility restoration activities was to enable building occupants to return to work quickly.
Delayed Health Response
Standing water and wet materials are a breeding ground for microorganisms − such as viruses, bacteria and mold. They can cause disease, trigger allergic reactions, and continue to damage materials long after the moisture intrusion or flood. Microorganisms brought into a building can penetrate into soaked, porous materials such as carpet and drywall, and later be released into the air. High humidity and moist materials provide ideal environments for the growth of microorganisms that are always present inside of buildings. Long-term increases in humidity can also foster the growth of dust mites, which may cause allergic reactions and asthma.
Mold requires an organic food source, moisture and time to grow and develop. As the moisture concentrations in building materials decrease, mold growth on the materials may slow down but still remain present. Any future increases in moisture content may result in a reemergence of mold.
Complaints and allegations of poor IAQ are not usually reported during the initial reoccupation period. Within a few months, however, the number of IAQ complaints may begin to increase due to odors and perceived or actual physiological responses. In response to the complaints, environmental professionals are retained to evaluate the indoor air quality and identify the potential source(s) of the complaint. By this point, identifying the potential contamination source(s) is difficult. Continuous use of the HVAC system has reduced elevated moisture content in building materials to normal concentrations. Cleaning of the carpet and painting of the damaged walls and ceiling have covered the visual signs of water damage and bacterial or mold
contamination. Without these indicators of moisture intrusion and potential damage, investigators are left to rely on interviews with facility staff, destructive investigations into wall and ceiling cavities, and sampling to determine the existing damage. Recommendations for the remediation of identified damages are often vague, to allow for identification of hidden contamination. These unforeseen areas of contamination can result in a subsequent increase in remediation costs.
Recommended Response
So how do facilities reduce the risks associated with previous hurricane, flood, or large water intrusion events? The first step is to identify facilities that were impacted by these events. An investigation of the remediation activities, conducted at the identified facilities after the water intrusion, should be completed. Buildings that were not fully investigated should be evaluated for potential bacteria or mold contamination behind baseboards and wallpaper, and within ceiling and wall cavities. Facilities with identified bacterial or mold contamination should be addressed immediately.
For most cases, if visible mold growth is present, sampling is not needed. Since there are no federal or state promulgated limits for mold or mold spores, sampling results should not be used to determine if a building’s air quality is in compliance with federal mold guidelines. Other potential pitfalls with air sampling include collecting an inadequate number of air samples, inconsistency in sampling protocols, and not collecting outdoor samples. Surface sampling may be useful to determine if a remediated area was cleaned adequately, but the sampling should only be conducted by professionals experienced in designing mold sampling protocols, sampling methods, and interpreting the sample laboratory results. Sample analysis should follow the analytical methods recommended by the American Industrial Hygiene Association (AIHA), or the American Conference of Governmental Industrial Hygienists (ACGIH). Sampling may also be considered when litigation is involved or may occur, when the mold source is unknown, or if health concerns are a problem.
Summarized below are some key steps that should be taken in response to moisture intrusion events:
- Consult a Certified Industrial Hygienist (CIH) throughout the process
- Select a remediation manager
- Determine the scope of mold or bacteria issues and identify type of materials damaged
- Communicate with building occupants throughout process as appropriate to the situation
- Identify the source or cause of water or moisture problem
- Plan remediation and interpret regulatory guidelines for level of protectiveness to match project
- Select personal protective equipment (PPE)
- Select containment equipment
- Select remediation personnel or team
- Choose between outside or in-house expertise for remediation
- Permanently correct water or moisture problem(s)
- Remediate the damages
- Clean and dry wet materials, assure that no suspect visible mold damages are present on materials
- Discard moldy items that can’t be cleaned
- Check for return of moisture and mold problem
- If hidden bacteria or mold is discovered, reevaluate plan
HETI…Experienced Environmental Health & Safety Professionals
Several buildings within the U.S. are faced with the dilemma described above. Unfortunately, carpet
replacement and re-painting of interior surfaces does not fully remediate bacteria and mold contamination.
HETI can assist in assessing facilities for these potential sources of contamination. We can provide a
workplace evaluation for these hazards and provide appropriate and feasible solutions for their remediation.
HETI can also assist in the development of moisture intrusion plans to provide a plan of action for the next
hurricane, flooding, or moisture intrusion event.
To find out more about this and other HETI EHS and industrial hygiene services, please contact us.
Michael Henderson, PhD, CIH
Senior Industrial Hygienist
Phone: 407.249.9322
development@hetiservices.com