OSHA RCS Silica in Construction – Silica in Construction, Integrated Water Delivery System, Exposure Assessment, Medical Surveillance, Respiratory Protection

STANDARD: 1926.1153(c)(1); 1926.1153(d)(2)(vi); 1926.1153(h)(1)(i)

March 4, 2019

Mr. Steven High
High Environmental Health & Safety Consulting Ltd.
1866 Colonial Village Lane, Suite 110
P.O. Box 10008
Lancaster, Pennsylvania 17605-0008

Dear Mr. High:

Thank you for your letter to the Occupational Safety and Health Administration’s (OSHA) Directorate of Construction (DOC). You have specific questions regarding the requirements of OSHA’s Respirable Crystalline Silica (RCS) Standard for the construction industry, 29 CFR 1926.1153. DOC referred the below questions related to health and industrial hygiene to OSHA’s Directorate of Enforcement Programs (DEP) for this response. DOC responded separately to your questions on fall protection. This letter constitutes OSHA’s interpretation only of the requirements discussed and may not be applicable to any questions not delineated within your original correspondence. Your paraphrased questions and our responses are below.

Question 1: In regards to Table 1 of the RCS standard for construction, what does OSHA mean by an “integrated water delivery system?” Can the system be designed and installed by the employer? If so, what are the requirements for construction of this system? Does the system need to be connected to the tool in some way to be considered integrated? Would an independent pressurized water sprayer operated by a second employee meet the requirements of an “integrated water delivery system?”

Response: Seven of the entries on Table 1 use the term “integrated water delivery system.” (See 29 CFR 1926.1153(c)(1)(i)-(ii), (iv)-(vi), (xii)-(xiii)). As stated in the preamble to the RCS standard, “OSHA is requiring the use of an integrated water delivery system supplied by the equipment manufacturer…. OSHA is requiring the use of systems that are developed in conjunction with the tool because they are more likely to control dust emissions effectively by applying water at the appropriate dust emission points based on tool configuration and not interfere with other tool components or safety devices.” (81 FR 16719).

Thus, an “integrated water delivery system,” for purposes of Table 1 of the RCS standard for construction, must be designed, developed, and supplied by the manufacturer specifically for the tool in use, and must be operated and maintained in accordance with the manufacturer’s instructions related to minimizing dust emissions. The system must also be connected to the tool to be considered integrated. Integrated water delivery systems designed for blade cooling meet the requirements of Table 1, as these systems have been found to effectively suppress respirable dust. (81 FR 16720).

Because the system must be supplied by the tool manufacturer, a water delivery system designed by the employer will not meet the requirements of Table 1, but may be used in accordance with paragraph (d) of the standard (see Question 2, below). In addition, an independent pressurized water sprayer operated by a second employee does not meet the requirements of an integrated water delivery system.¹ For a description of each Table 1 entry and required water delivery systems, see OSHA’s Small Entity Compliance Guide for the Respirable Crystalline Standard for Construction, at https://www.osha.gov/Publications/OSHA3902.pdf.

Question 2: Are exposure assessments required as a result of not meeting the criteria for an integrated water delivery system as specified in Table 1?

Response: Yes. Under the RCS standard for construction, employers with employees performing tasks listed on Table 1 must either fully and properly implement the engineering controls, work practices, and respiratory protection specified for the task on Table 1 or assess and limit the exposure of the employees in accordance with paragraph (d). (29 CFR 1926.1153(c)(1)). The preamble to the RCS standard explains that, “Employers may implement other controls or wet method configurations if they determine that the alternative control is more appropriate for their intended use. However, employers who choose to use controls not listed on Table 1 will be required to conduct exposure assessments and comply with the PEL in accordance with paragraph (d) of the standard for construction.” (81 FR 16719). Therefore, employers who choose to use controls that are not compliant with Table 1, such as water delivery systems designed and installed by the employer, are required to comply with paragraph (d).

Question 3: With respect to 29 CFR 1926.1153(d)(2)(vi), Employee Notification of Assessment Results, when does OSHA consider an exposure assessment to be completed, and when does the five-working-day period for notification start? Does this notification start time change if the employer uses a third party to perform the exposure assessment, rather than conducting the exposure assessment internally?

Response: The preamble to the RCS standard states that, for employers following the performance option in paragraph (d)(2)(ii) of the standard for construction, the 5-day period for employee notification “commences when the employer completes an assessment of employee exposure levels.” (81 FR 16769). The exposure assessment under the performance option is considered completed when the employer has characterized an employee’s 8-hour time-weighted average (TWA) exposure to RCS based on air monitoring data, objective data, or a combination of the two.

For employers following the scheduled monitoring option in paragraph (d)(2)(iii) of the standard for construction, the 5-day period for notification “commences when monitoring results are received by the employer.” (81 FR 16769). If the employer is using a third party to perform the exposure assessment, the employer is considered to have “received” the monitoring results when the consultant communicates the monitoring results to the employer. Similarly, if the employer is conducting the assessment internally, the employer is considered to have “received” the monitoring results when the laboratory communicates the results to the employer. However, employers should exercise due diligence to avoid unreasonable delay in receiving results from the consultant or the laboratory. In addition, employers should note that the standard does not provide employers with extra time to study the results, meet with employees to discuss them, perform quality assurance checks on the results, draft a formal report, or complete similar actions. (See 81 FR 16769).

Question 4: If an employer requires respiratory protection for employees whose documented exposures to RCS are below the PEL, does such respirator use count for purposes of determining whether medical surveillance must be made available to those employees under paragraph (h) of the construction standard?

Response: No. Employers must make medical surveillance available to each employee who will be required under the RCS standard for construction to use a respirator for 30 or more days per year. (29 CFR 1926.1153(h)(1)(i)). The standard requires respirator use where respirator use is specified on Table 1 (when employers are following the specified exposure control methods) or where exposures exceed the PEL (when employers are following the alternative exposure control methods). (81 FR 16816). A day in which a respirator is only worn because it is required by the employer (but not by the RCS standard) does not count toward the 30-day threshold for medical surveillance. Please note that employers must comply with OSHA’s respiratory protection standard (29 CFR 1910.134) whenever employees use respirators to protect against RCS exposures, regardless of whether such use is required by the RCS standard, required by the employer, or voluntary by employees.

Question 5: If a task on Table 1 of the RCS standard for construction requires the use of a respirator for work taking four hours or less, but that task is performed for only 10 minutes a day, does that 10-minute period of respirator use count towards the 30 days?

Response: Yes. If the employee is required by the standard to wear a respirator at any time during a day (even for times less than one hour), then that counts as one day of respirator use. This is explained in the preamble, which states, “if an employee is required to wear a respirator at any time during a given day, whether to comply with the specified exposure control methods in paragraph (c) or to limit exposure to the PEL under the construction standard for respirable crystalline silica, that day counts toward the 30-day threshold.” (81 FR 16816).

Question 6: How does OSHA consider extended workdays for purposes of counting days of respirator use? If an employee works 29 days at 14 hours a day within the year performing high-exposure silica tasks which require a respirator, would they be exempt from medical surveillance?

Response: OSHA considers the 14-hour shift you describe in your letter to constitute a single day for the purpose of determining the number of days of respirator use under the medical surveillance provisions. (See 29 CFR 1925.1153(h)(1)(i)). Thus, if an employee works one 14-hour shift and is required to wear a respirator under the RCS standard at any time during that shift, the employee will be considered to have worn a respirator for one day for purposes of paragraph (h)(1)(i) of the construction standard. The employee described in your question, who is required to wear a respirator for 29 fourteen-hour work shifts in a year (and is not required to wear a respirator at any other time under the RCS standard), does not meet the threshold of 30 days of respirator usage for medical surveillance purposes.²

Please note that the requirement is for employers to offer an examination to employees who “will be” required to use a respirator under the RCS standard for construction for 30 or more days per year. (29 CFR 1926.1153(h)(1)(i)). Therefore, eligibility for medical examinations is based on expected days of respirator use. Employers must make a reasonable estimate of the number of days that each employee will be required to wear a respirator and offer medical examinations to those employees expected to wear respirators for 30 or more days in a twelve-month period.

Thank you for your interest in occupational safety and health. We hope you find this information helpful. OSHA’s requirements are set by statute, standards, and regulations. Our letters of interpretation do not create new or additional requirements but rather explain these requirements and how they apply to particular circumstances. This letter constitutes OSHA’s interpretation of the requirements discussed. From time to time, letters are affected when the Agency updates a standard, a legal decision impacts a standard, or changes in technology affect the interpretation. To assure that you are using the correct information and guidance, please consult OSHA’s website at http://www.osha.gov. If you have further questions, please feel free to contact the Office of Health Enforcement at (202) 693-2190.

Sincerely,

Patrick J. Kapust, Acting Director
Directorate of Enforcement Programs

OSHA RCS Construction

¹ The Table 1 entry for jackhammers does not refer to an “integrated water delivery system.” It does, however, give employers the option to use the jackhammer with a “water delivery system that supplies a continuous stream or spray of water at the point of impact.” (29 CFR 1926.1153(c)(1)(x)). Because this entry does not require an integrated water delivery system, the water delivery system described in your letter, wherein a second employee applies water at the point of impact via a separate water sprayer, could be compliant with Table 1 requirements for the use of jackhammers with wet methods.

² For employers following the alternative exposure control methods set forth in paragraph (d), determinations of whether exposures are above the PEL (and thus whether respirators are required) must account for the extended nature of work shifts that are longer than eight hours. As explained in the preamble to the RCS standard, this can be done in one of two ways: “sampling the worst (highest exposure) eight hours of a shift or collecting multiple samples over the entire work shift and using the highest samples to calculate an 8-hour TWA.” (81 FR 16765; see also OSHA’s Technical Manual at Section II, Chapter 1, III.E, at https://www.osha.gov/dts/osta/otm/otm_ii/otm_ii_1.html#extended_workshifts).

OSHA RCS Construction

OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA’s interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA’s website at https://www.osha.gov.

OSHA RCS Construction

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