Generalized statements about hazardous components of concern within PC often conflict, possibly due to different definitions or intended context. For example, NIOSH defines PC as containing less than 1 percent silica of the crystalline variety, while OSHA lists PC as a substance that may contain greater than 1 percent crystalline silica. Additional inconsistencies become evident when comparing OSHA’s documents with trade, manufacturer, and geological references. Consequently, IHs must interpret product and material data.  OSHA’s Hazard Communication Standard requires hazard classifications for all hazardous chemicals manufactured, imported, or distributed in the United States. In addition to obtaining the safety data sheets, IHs should contact manufacturers and request additional studies or product information (for example, recommended devices for control of hazards, studies performed on personal protective equipment). IHs should also review the material’s physical and chemical properties as well as any hazards posed by the substance. Commonly cited health effects of PC include irritation of the eyes, skin, and nose; cough or expectoration; and exertional dyspnea (breathing difficulty), wheezing, and chronic bronchitis. The effects of exposure to cement dust have been associated with many common preexisting health conditions, including asthma and even periodontal tissue destruction. There are fewer studies that broadly examine the adverse health effects of cement dust than the specific hazardous components within cements.  PC exposure routes are inhalation, ingestion, and contact with skin or eyes with the potential to cause both surface and deep tissue damage. Generally, damage increases cumulatively with duration of exposure and concentration.  Two well-documented hazardous components within PC are RCS and hexavalent chromium [Cr(VI)].

RCS is among the most common carcinogens to which workers are exposed. Breathing RCS dust can cause silicosis, and it is well established that exposure to RCS increases the risk for respiratory diseases, lung cancer, and cardiovascular disease as well as many other health problems.  Workplaces that use PC and other cement products must now comply with OSHA’s new RCS standards, CFR 1926.1153 for construction and CFR 1910.1053 for both general industry and maritime. Both regulations have a PEL of 50 µg/m³ as an eight-hour time-weighted average. As clarified in an OSHA interpretation letter, materials (whether wet or dry) containing 0.1 percent or more crystalline silica by weight or volume are generally covered by OSHA’s HAZCOM requirements and should be noted on SDSs. When the RCS regulation is triggered, OSHA’s HAZCOM requires addressing at least cancer and effects to the lungs, immune system, and kidneys.

Cr(VI) can lead to the development of skin sensitization, which is called allergic contact dermatitis. Once sensitized, reactions can be triggered from even small Cr(VI) exposures. Workers can remain sensitized for extended periods. Medical testing for Cr(VI) sensitization is available. When dry, PC is easily airborne, coating nearby workers and surfaces. Dry PC is abrasive and hygroscopic (water-absorbing). It can have a corrosive alkaline (caustic) pH as high as 12 to 13. Third-degree cement burns may develop after only two hours of contact; therefore, workers cannot rely on pain or discomfort as warning signs—at that point, substantial damage may have already occurred. Burns can become worse even after washing the area because the corrosive burn can penetrate skin and beyond, reaching down to muscle and bone. Skin contact with PC can also lead to chrome ulcers.  Dry PC is considered less caustic compared with wet PC, but bodily accumulations of dry PC can activate with moisture (for example, moisture in eyes, sweat, the respiratory system, and water mists). Corrosive moisture can also wick from uncured PC to contaminate a worker’s clothes, tools, and materials.  Engineering controls (for example, barricades and draft control) should be used to reduce the formation and spread of airborne dusts. Long contact times with unprotected skin can be avoided through use of administrative controls and PPE, but workers can often experience long contact times if the PPE itself becomes contaminated. The NIOSH Pocket Guide to Chemical Hazards lists respirator recommendations based on concentrations. OSHA mandates that employers provide washing and hygiene facilities with clean water; nonalkaline, pH-neutral soap; and clean towels for workers exposed to PC. Rinsing or washing of hands in the same water used for cleaning tools is ineffective—the pH of contaminated water will not be affected by the settling of solids to the bottom, a phenomenon that workers often falsely interpret as an indication of cleaner water. OSHA, NIOSH, and ACGIH publish airborne exposure limits for PC and its components, addressing respirable fraction, total dust, and mineral dust. In addition to its new standards specific to RCS, OSHA has an inhalation PEL for dry PC of 15 mg/m³ for total dust and 5 mg/m³ for respirable dust. OSHA has construction regulations (29 CFR 1926.55) for gases, vapors, fumes, dusts, and mists and general industry regulation (29 CFR 1910.1000) for air contaminants of mineral dusts and other related materials. This article does not address the particulars to consider when creating sampling plans and interpreting data. Individuals who perform such tasks should review the details of available methods and select a method applicable to the material targeted for sampling (for example, RCS as quartz, cristobalite). Considerations should be made for contributions from background and simultaneous activities, whether a representative pure bulk sample is necessary for comparison, impacts of PC morphing between phases (at least 22 different solid phases have been identified, some of which are not stable), and the validation range of the analytical method for target material. Bear in mind that airborne background concentrations on construction sites may be affected by disturbance of soil and cement dust contamination from other employers. Airborne concentrations are affected by the location of the work and environmental conditions. Analytical laboratories should be consulted for guidance and critical information such as sampling interferences, which affect the labs’ ability to detect lower levels of analyte.  PC hazard communication must cover Cr(VI), worker access to hygiene facilities, and the importance of hygiene. Show workers how to remove PPE safely—that is, without self-contamination. To help workers avoid tracking contaminants to their vehicles and homes, employers should consider providing changing facilities and lockers in addition to adequate hygiene facilities. As this article demonstrates, substantial confusion can result when IHs try to interpret generally available information on PC. Although the industrial hygiene field is indeed known to be a science and an art that rests on professional judgment, we must create consensus on the definitions and hazards of PC.  My experience has shown that many workers and supervisors fail an informal “pop quiz” on the basics of working with PC safely and the substance’s possible long-term effects. I challenge you to gauge worker knowledge at all levels and to determine if your organization can benefit from refresher training.   The author of the information herein is a federal government employee. The content is unrelated to official work and/or duties and does not necessarily represent any position or opinion of the government. The author thanks Eugene Satrun and Jerome Spear of AIHA’s Construction Committee for reviewing this article.

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