AIHA Testimony on the OSHA Proposed Silica Standard

Posted March 21, 2014

AIHA Vice President Daniel Anna testified on behalf of the association at the March 21, 2014, public hearing for OSHA's proposed rule on occupational exposure to respirable crystalline silica. His testimony is below.


My name is Daniel Anna and I am Vice President of the American Industrial Hygiene Association (AIHA).  I am a certified industrial hygienist, a certified safety professional and have been involved in the occupational health and safety profession for nearly 25 years.  It is a privilege for me to represent the AIHA at this public hearing. 


AIHA is the premier association serving the needs of professionals practicing industrial hygiene in industry, government, labor, academic institutions, and independent organizations.  The AIHA mission is to promote healthy and safe working environments by advancing the science, principles, practice, and value of industrial and occupational hygiene.  Our members recognize that a healthy workforce is essential to the success of American industry, our national economy, and our position in the global economy.


AIHA submitted extensive comments that appear in the federal docket.  I would like to use this opportunity to summarize some of AIHA’s key points.


As stated by OSHA in the announcement of the proposed rule “Exposure to silica can be deadly, and limiting that exposure is essential.”  Ultimately, the question is “will this proposal result in improved employee health and safety?”  AIHA answers a resounding “yes”, and supports OSHA’s efforts to move forward with the proposed rule that helps to protect worker health and reduce illnesses related to silica exposures.


AIHA provided responses to questions raised in the Notice of Proposed Rulemaking published in the Federal Register.  These responses included following comments on several aspects of the proposed regulation:


  • The proposed standard defines “respirable crystalline silica as: “airborne particles that contain quartz, cristobalite, and/or tridymite and whose measurement is determined by a sampling device to meet the characteristics for respirable-particle-size-selective samplers specified in the International Organization for Standardization (ISO)7708:1995: Air Quality-Particle Size Fraction Definitions for Health-Related Sampling.” 


This definition would consider the entirety of a sample of dust containing any miniscule but detectable quantity of quartz, cristobalite or tridymite, as respirable crystalline silica.  AIHA recommends that OSHA change the beginning of the definition to read: “airborne particles of quartz, cristobalite, and/or tridymite …” to clarify that the silica content is what is considered in the determination of the concentration.

  • Compliance with the PEL should be required until sufficient objective data sets are assembled to account for the variability of workers, tasks and materials.  Then, acceptable work practice and workplace controls can be assigned to tasks and activities. When the performance of these controls are verified, techniques such as work permits, job observations and workplace assessments can be conducted real time to see if the controls are being properly administered.  Employers implementing strategies other than monitoring should have researched the control appropriateness and developed strategies to ensure the controls are working on a day-to-day basis.

  • The AIHA endorses the concept of Table 1 and the option it provides to construction contractors.  Although AIHA encourages air monitoring as an important part of an overall worker exposure assessment program, the reality is that potential worker exposures on a construction site are constantly changing.  By the time sample are collected and analyzed tasks may have been completed and workers have dispersed to other jobs, which minimizes the usefulness of the monitoring results.  Use of Table 1 allows contractors to anticipate and implement protective measures from the start of the project and avoid the expense of air monitoring that would provide only minimal information.


Table 1 also allows contractors to anticipate control needs and factor costs into a job bid to produce an awarded contract that will contain the needed resources to perform the job with reduced silica exposures.  Smaller contractors without dedicated safety professionals will benefit because the requirements needed to properly protect workers will be more clearly defined.  Project owners will be able to evaluate bids to ensure that contractors have incorporated the costs of silica control into their proposal.


  • Many silica producing tasks on construction sites are of limited duration during a shift.  The AIHA endorses the dual table format characterizing exposures as either less than or greater than 4 hours in duration.  This acknowledges that a limited duration of exposure will provide a level of protection by reducing a worker’s 8 hour TWA exposure, and may reduce the cost associated with respirator use during limited duration activities where other controls are properly implemented. 

  • While AIHA endorses the use of Table 1 as a compliance option, there are six recommendations for OSHA to consider:
  1. Several Engineering and Work Practice Control Methods state that equipment should be operated “…such that no visible dust is emitted from the process”.  AIHA is concerned that this is a subjective determination and recommends this requirement be removed.  The competent person, operator, and employer are responsible for ensuring the proper use and functioning of the equipment and can evaluate the controls on a case by case basis to determine if excessive dust is being released. 
  2. Several of the tasks listed in the Table do not require any supplemental respiratory protection when the task duration is less than four hours.  AIHA recommends that for any task in Table 1 where no respirator requirement is listed, OSHA require the employer to provide a minimum 1/2 face piece respirator upon employee request or when a competent person determines that respiratory protection is needed. 
  3. Because engineering and work practice control methods play a critical role in exposure control, AIHA recommends that OSHA require the employer to have a competent person whenever Table 1 is used for compliance purposes – regardless if respirator use is required or not.  A competent person should be available to verify that the controls are adequate for the specific situation.  The AIHA White Paper – Recommended Skills and Capabilities for Silica Competent Persons can be referenced as a non-regulatory guidance document.
  4. AIHA recommends that for commercially available engineering controls (e.g. water spray, LEV) OSHA require that employers follow the manufactures’ instructions for installation, use and maintenance of the equipment – unless there is written variance from the manufacturer.
  5. AIHA recommends OSHA make the respirator requirements of Table 1 performance oriented, instead of specifying a particular respirator type.  AIHA recommends specifying only that the respirator used meets or exceeds a specific assigned protection factor (APF) as documented in 29CFR1910.134.  As Table 1 reads now, some employers may believe that the specified respirator is the type that must be used.  Citing only the minimum APF makes it clear that any NIOSH approved respirator meeting or exceeding that APF may be used. 
  6. OSHA should clarify what is included when determining if the operation duration is less than or greater than 4 hours.  AIHA recommends that time include overall run time of the tool, positioning of materials, preparing and measuring stock materials, and adjustment of tools.


Medical surveillance.  Workers exposed to silica deserve medical surveillance to identify early signs of disease.  Workers who are exposed to higher levels and those who wear respirators should be a high priority for medical surveillance.  OSHA may want to consider reducing the frequency of exams for younger workers or reducing the frequency of tests like X-rays, as is done in the Asbestos standard. 


The proposed 30 day trigger for medical exams is problematic for construction, where workers frequently change jobs and employers.  Because of issues related to tracking days of exposure, AIHA recommends that OSHA reconsider how medical exams are triggered for a transient construction workforce.

Finally, the industrial hygiene assessments and exposure monitoring are recognized in the proposed rule text to be "fairly challenging".  The standard requires employers to conduct exposure monitoring to ensure dust controls are working properly, but is mute with respect to the qualification of those performing professional industrial hygiene tasks.  The requirements for conducting "industrial hygiene” assessments and using "industrial hygienists" are written into the proposed Standard, yet no comments related to the "certification" of the industrial hygienist are included.  AIHA strongly recommends that at a minimum, the professional and technical oversight of the industrial hygiene aspects listed within the Standard be performed under the cognizance of a "Certified Industrial Hygienist (CIH)".  The inclusion of this nominal requirement ensures that the proper knowledge, skills, and abilities are held by the professionals performing this most important aspect of the proposed Standard.


In conclusion, AIHA appreciates the opportunity to work with OSHA to help achieve the mutual goal of protecting American workers from exposure to crystalline silica.  As the agency moves forward, the AIHA offers its breadth of experience as a resource and look forward to further opportunities to work with the agency on this and similar issues and regulatory priorities.


On behalf of AIHA, thank you for this opportunity to participate and present our views.  If AIHA can be of any further assistance, please contact me.  Thank you.


I would be happy to take any questions you may have.