Construction is considered a high-hazard industry where workers engage in activities that may expose them to potentially serious hazards. For example, the floorcovering installer and subfloor surface preparation technician are exposed to a wide range of potential hazards. Two common hazards that are encountered on a weekly basis (mold, mildew and respirable crystalline silica) have been neglected for years. Only in the past three years have OSHA standards for respirable crystalline silica been implemented in the construction industry.


Mold and Mildew

Mold and mildew are typically easy to identify by visual and odor indications. Visible signs of mold or mildew may be found on the subfloor, underlayment, floorcovering backing, the flooring surface and even walls. Occasionally, mold and mildew conditions may not be readily identifiable before a floorcovering removal is initiated. If discovered after work has begun, all flooring work should be halted until the issue has been mitigated.  

Mold and mildew are terms often used generically but have differing characteristics. While both are fungi that need food, water, oxygen, and prefer humidity levels above 60% for survival, they differ in several ways. Mold tends to have a higher profile and can even have a fuzzy appearance, whereas mildew has a flat profile. Mold exhibits darker colors such as deep greens and black. Mildew may begin as white, turn brown or gray, and eventually convert to a white powdery substance.  

The U.S. Environmental Protection Agency (EPA) addresses how to deal with mold and mildew in two publications “A Brief Guide to Mold, Moisture and Your Home” (EPA 402-K-02-003) and “Mold Remediation in Schools and Commercial Buildings” (EPA 402-K-01-001). The latter publication provides a two-page checklist guide for mold remediation. Depending on the mold or mildew condition present, remediation options range from cleanup measures using PPE and biocide cleaning chemicals, to hiring a professional mold and mildew remediation contractor to address the condition. 


Crystalline Silica

Crystalline silica is a common mineral that is found in materials such as sand, stone, concrete, brick, and mortar. When someone cuts, grinds, sands or drills materials that contain crystalline silica, exceedingly small dust particles are created. These tiny particles are known as “respirable” particles, or as in this case, “respirable crystalline silica”. The floorcovering installer or subfloor surface preparation technician may be exposed to respirable crystalline silica during common tasks such as sanding or grinding subfloor surfaces to obtain acceptable flatness and levelness, or when a concrete surface is non-porous and requires a porous surface, or when the Concrete Surface Profile (CSP) must be changed to accommodate a product application.  

OSHA estimates that over two million construction workers are exposed to respirable crystalline silica annually. The OSHA standard that addresses respirable crystalline silica (29 CFR 1926.1153) requires employers to limit worker exposures and to take other steps to protect workers. Employers have two options, they can either use a control method as laid out in Table 1 of the construction standard, or they can measure workers’ exposure to silica and independently decide which dust controls work best to limit exposures in their workplaces to the permissible exposure limit (PEL).  

Known hazards to long term exposure of respirable crystalline silica includes silicosis, an incurable lung disease (that leads to disabling respiratory conditions), chronic obstructive pulmonary disease (COPD), kidney disease and development of autoimmune disorders. These occupational diseases are life altering. Even though known and with the widespread implementation of OSHA standards that mitigate the cause, there are still many instances where the standards are not adequately adhered to or unfortunately ignored altogether. 


Respirable Crystalline Silica Compliance 

OSHA’s Respirable Crystalline Silica Standard for Construction detailed in 29 CFR 1926.1153 provides two alternatives for compliance. Table 1 in the standard matches 18 common construction tasks with effective dust control methods, such as using water to keep dust from getting into the air or using a vacuum dust collection system to capture dust. In some operations, respirators may also be needed. Employers who follow Table 1 correctly are not required to measure workers’ exposure to silica from those tasks and are not subject to the Permissible Exposure Level (PEL). However, employers who do not fully implement the control methods on Table 1, must do the following: 

  • Determine the amount of silica that workers are exposed to if it is, or may reasonably be expected to be, at or above the action level of 25 µg/m3 (micrograms of silica per cubic meter of air), averaged over an 8-hour day 
  • Protect workers from respirable crystalline silica exposures above the PEL of 50 µg/m3, averaged over an 8-hour day 
  • Use dust controls and safer work methods to protect workers from silica exposures above the PEL 
  • Provide respirators to workers when dust controls and safer work methods cannot limit exposures to the PEL 
EQUIPMENT/TASK: (XIII) WALK-BEHIND MILLING MACHINES AND FLOOR GRINDERS
Engineering and work practice control methods Required respiratory protection and minimum assigned protection factor (APF)
≤ 4 hours/shift > 4 hours/shift
Use machine equipped with integrated water delivery system that continuously feeds water to the cutting surface None None
Operate and maintain tool in accordance with manufacturer's instructions to minimize dust emissions Required Required
OR
Use machine equipped with dust collection system recommended by the manufacturer None None
Operate and maintain tool in accordance with manufacturer's instructions to minimize dust emissions Required Required
Dust collector must provide the air flow recommended by the manufacturer, or greater, and have a filter with 99% or greater efficiency and a filter-cleaning mechanism Required Required
When used indoors or in an enclosed area, use a HEPA-filtered vacuum to remove loose dust in between passes Required Required

Regardless of which exposure control method is used, all construction employers covered by the standard are required to: 

  • Establish and implement a written exposure control plan that identifies tasks that involve exposure and methods used to protect workers, including procedures to restrict access to work areas where high exposures may occur 
  • Designate a competent person to implement the written exposure control plan 
  • Restrict housekeeping practices that expose workers to silica where feasible alternatives are available 
  • Offer medical exams-including chest X-rays and lung function tests every three years for workers who are required by the standard to wear a respirator for 30 or more days per year 
  • Train workers on work operations that result in silica exposure and ways to limit exposure 
  • Keep records of exposure measurements, objective data and medical exams 

Industry education associations have sample guidelines for the employer to meet these required OSHA standards and OSHA has a downloadable compliance guide for work practice controls, exposure assessments, respirator use, medical surveillance, written exposure control plans, and other aspects of compliance of the standard. Another valuable tool at www.osha.gov/silica-crystalline/construction is a customizable PowerPoint presentation that provides employers and others for training on compliance with OSHA’s respirable crystalline silica standard for construction.