1. Silica in Construction
OSHA Std

2. Silica in Industry
OSHA Std

3. What is Silica? Silica is Quartz
Quartz (silica) is found naturally in almost all rock, sand and soil.
It is also found in concrete products and bricks.
It is sometimes found in sandblasting (abrasive blasting) grit and is called “silica sand”.
“Silica dust is generated from cutting, grinding, drilling, sanding sandblasting, or abrasive blasting, on concrete, bricks or masonry blocks. A common brand name silica sand used for abrasive blasting in this area is Lane Mountain. If the blasting grit contains silica, it will usually be labeled as silica sand or as containing quartz, or crystalline silica.”

4. WORKPLACE EXPOSURES
OSHA reports 2.2 million workers are exposed to respirable crystalline silica.
The majority (1.85 million) are in the construction industry.
Exposures occur when workers cut, grind, crush, or drill silica-containing materials.

5. Inhaled silica dust scars the lungs
Silica Health Hazards
Inhaled silica dust scars the lungs
A lung disease called “silicosis” is caused by breathing of dust containing silica.
The dust causes “fibrosis” or scar tissue formation in the lungs.
This reduces the lung’s ability to extract oxygen from the air.
There is no cure!
“Because the effects of silica is irreversible, it is considered to be a serious health hazard on many construction sites.”

6. What are the symptoms of silicosis?
Silica Health Hazards
What are the symptoms of silicosis?
Early stages go unnoticed.
Continued exposure results in shortness of breath during exercise.
Prolonged high exposure can lead to extreme shortness of breath, chest pain, respiratory failure and death.
“Workers who developed these symptoms often did not even know they were breathing silica dust or that it caused lung damage.” 6

7. ‘TYPES’ OF SILICOSIS Simple chronic silicosis Accelerated silicosis
From long-term exposure (10-20 years) to low amounts of silica dust.
Accelerated silicosis
Occurs after exposure to larger amounts of silica over a shorter period of time (5-10 years).
Acute silicosis
From short-term exposure to very large amounts of silica dust.

8. Lung Cancer There is an association between silicosis and lung cancer
Over 500 silica related lung cancer deaths in construction in 2004 – Over 10 a week
Silica is the second most important cause of occupational lung cancer after asbestos
1) It might be that it is necessary to have silicosis before you get silica induced lung cancer.
The association between silicosis and lung cancer is more pronounced in smokers.
Commonest cause of lung cancer is smoking (responsible for 90% cases).
2) However, HSE estimates that approximately 2,000 deaths per year in construction are due to occupational lung cancers, most of which asbestos-related.

9. Chronic Obstructive Pulmonary Disease (COPD)
Persistent obstruction of airflow into lungs
Irreversible (unlike asthma)
Progressive
Main cause is smoking
Silica exposure associated with COPD
Construction workers 2 to 3 times risk
Symptoms: breathlessness, cough with phlegm
COPD is a disorder in which there is persistent obstruction of airflow into the lungs. COPD encompasses chronic bronchitis and emphysema.
2) COPD mostly irreversible. A small portion of the narrowing in airways can be reversed in some people with inhalers etc but most can’t. Overall, once you have developed the condition you are stuck with it. Asthma involves reversible obstruction of airflow into the lungs.
3) Condition produces symptoms in middle or old age: SOB, cough with phlegm
4) Both diseases progressive over time unless the cause is removed unlike silicosis.
5) HSE estimates 4,000 deaths/year across industry due to COPD due to occupational causes.
Construction workers show two to 3-fold increase in COPD illness and mortality compared to age and smoking matched reference groups. In other words, working in construction is a risk factor for COPD regardless of smoking habits.
Causative agents include wood dust and silica.
6) As well as background breathlessness, cough with phlegm, people with COPD are more likely to get chest infections.

10. What’s the Problem?
Silica is found in sand but is not a hazard as it is not fine enough to be inhaled – see next slide
Silicon dioxide (SiO2)

11. Why is it a Problem? Particles need to be “respirable” to cause harm
Issue is Respirable Crystalline Silica or RCS
RCS particles can penetrate to deep lung
Cutting, drilling, grinding or polishing silica containing products such as kerbing, paving, blocks and concrete produces airborne dust. This contains a range of crystalline silica particle sizes, some of which can be inhaled.
The larger inhaled particles enter the main passageways of the lungs (bronchi) but are prevented from passing through the very small passageways due to their size. They tend to get coughed out.
3) Respirable particles are the tiny particles which are small enough to reach deep into the lung to the alveoli which are the little sacs at the end of the tiniest passage. Here oxygen is taken up by the blood and carbon dioxide is released from the blood into the air.
4) Freshly cleaved particles of RCS are more dangerous than ‘aged’ silica eg those generated during many common workplace tasks such as drilling, cutting, grinding or polishing.

12. Why is it a Problem? A micron is one millionth of a meter.
Human hair varies between 40 to 100 m thick.
Respirable dust = 10 m or less
The particles of sand are too big to be respired.
RCS is 10um or less so can be reach deep into the lung.
RCS is invisible under normal conditions.

13. OSHA Silica Standard
September 2013, OSHA published a Notice of Proposed Rulemaking (NPRM) for Occupational Exposure to Respirable Crystalline Silica.
First update since the original Permissible Exposure Limit (PEL) was adopted in 1971.
On March 25, 2016, OSHA published the long-awaited final rule.

14. CFR 1926 Respirable Crystalline Silica
Scope and application
Definitions
Specified exposure control methods (Table 1)
Alternative exposure control methods
Respiratory protection
Housekeeping
Written exposure control plan
Medical examination
Communication of hazards
Recordkeeping
Dates

15. Scope and Application
Applies to all occupational exposures to respirable crystalline silica in construction work, except where employee exposure will remain below 0.25 mg/m3 as an 8-hour Time-weighed average under any foreseeable conditions.

16. Written Exposure Control Plan Competent Person
The employer shall designate a competent person to make frequent and regular inspections of job sites, materials, and equipment to implement the written exposure control plan.
Competent Person - an individual who is capable of identifying existing and foreseeable silica hazards in the workplace and who has authorization to take prompt corrective measures to eliminate or minimize them.

17. Written Exposure Control Plan
Must contain at least the following elements
Description of tasks that involve silica exposure
Description of engineering controls, work practices and respiratory protection used for each task
Description housekeeping methods
Description of procedures used to restrict access to work areas, to minimize the number of employees exposed
Must be evaluated and updated at least annually
Must be readily accessible

18. New OSHA Limits Passed in 2016
Permissible Exposure Limit (PEL)
50 ug/m3 as an 8-hr TWA for all forms of
silica including quartz, cristobalite, and
Tridymite
Action Level
25 ug/m3 as an 8-hr TWA
(same as current ACGIH TLV)

19. 8-Hour TWA TWA = Time - Weighted Average Levels vary over
the shift duration
These limits protect from chronic diseases
8-hr TWA = (C1 x T1) + (C2 x T2) ….. (Cn x Tn)
480 min

20. 1926.1153 (c) Table 1 Specified Exposure Control Methods
For each employee engaged in a task identified in Table 1
Shall implement engineering controls, work practices, and respiratory protection required,
unless
Employer assesses and limits the exposure of the employee to respirable crystalline silica in accordance with paragraph (d)

21. Specified Exposure Control Methods Table 1
Employers who choose to follow engineering, work practice controls and respirator requirements in Table 1 do not have to conduct sampling or ensure employees are exposed below the PEL.

22. Specified Exposure Control Methods Table 1
18 Job Tasks covered in Table 1
Stationary masonry saws
Handheld power saws
Handheld power saws for cutting fiberglass
Walk-behind saws
Drivable saws
Rig-mounted core saws or drills
Handheld and stand-mounted drills
Dowel drilling rigs for concrete
Vehicle-mounted drilling

23. Specified Exposure Control Methods Table 1
18 Job Tasks covered in Table 1 (cont.)
Jackhammers and handheld powered chipping tools
Handheld grinders for mortar removal
Handheld grinders for other uses
Walk-behind milling machines and floor grinders
Small drivable milling machines
Large Drivable milling machines
Crushing machines
Heavy equipment and utility vehicles used to abrade or fracture silica-containing materials
Heavy equipment vehicles for tasks such as grading and excavating

24. Table 1: Specified Exposure Control Methods

25. Specified Exposure Control Methods
When implementing the control specified in Table 1:
For indoor tasks or tasked in enclosed areas, provided a means of exhaust as needed to to minimize the accumulation of visible airborne dust;
For tasks performed using wet methods, apply water at flow rates sufficient to minimize release of visible dust;
Where an employee performs more than one task on Table 1 during the course of a shift, and the total duration of all tasks combined is more than four hours, the required respiratory protection for each task is the respiratory protection specified for more than four hours per shift. If the total duration of all tasks on Table 1 combined is less than four hours, the required resp protection for each task if the respiratory protection for less than four hours per shift.

26. Specified Exposure Control Methods
When implementing the control specified in Table 1
For measures implemented that include an enclosed cab or booth:
Is maintained as free as practicable for settled dust;
Has door seals and closing mechanisms that work properly;
Has gaskets and seals in good condition and work properly
Is under positive pressure maintained through continuous delivery of fresh air;
Has intake air that is filtered through a filter that is 95% efficient
Where an employee performs more than one task on Table 1 during the course of a shift, and the total duration of all tasks combined is more than four hours, the required respiratory protection for each task is the respiratory protection specified for more than four hours per shift. If the total duration of all tasks on Table 1 combined is less than four hours, the required resp protection for each task if the respiratory protection for less than four hours per shift.

27. Alternative Exposure Controls
Employer shall ensure no employee is exposed in excess of PEL
Exposure Assessment – employer shall assess exposure of each employee who may be exposed at or above action level
Performance Option – Use “objective data” or sampling to determine which tasks are likely to cause exposure over the AL
Scheduled Monitoring – Perform initial sampling, for each employee, to determine which tasks cause exposure above the AL, then conduct periodic sampling afterwards

28. Alternative Exposure Controls
Performance Option – Use “objective data” or sampling to determine which tasks are likely to cause exposure over the AL
Scheduled Monitoring – Perform initial sampling, for each employee, to determine which tasks cause exposure above the AL, then conduct periodic sampling afterwards

29. Performance Option - Objective Data
Information such as:
Air monitoring data from industry-wide surveys or calculations based on the composition of a substance, demonstrating employee exposure to respirable crystalline silica associated with particular product or material or a specific process, task, or activity.
Data must reflect workplace conditions closely resembling or with higher exposure potential.

30. Objective Data - Recordkeeping
Shall include at least the following information:
The silica-containing material in questions
The source of objective data
The testing protocol and results of testing;
Description of the process, task, or activity on which the data were based; and
Other data relevant data

31. Scheduled Monitoring Option
If initial monitoring indicates exposures are below the AL, may discontinue monitoring for those employees
Periodic monitoring
At or above AL = repeat monitoring within 6 months
Above the PEL = repeat monitoring within 3 months
Must repeat monitoring until there are two consecutive measurements below AL

32. Alternative Exposure Controls
Employee Notification
Within 5 working days after, employer shall notify each affected employee in writing or by posting the results in an appropriate location accessible to all affected employees
When results indicate employees’ exposures are above the PEL, written notification with include the corrective action being taken to reduce exposures to or below the PEL.

33. Silica and Use of Respirators
Respirators must be used if silica dust can’t be controlled with water or ventilation or when specified in Table 1
either or
“One-piece dust masks can also be used, but are not recommended because they don’t always fit properly and can leak with prolonged use. Respirators may still be needed even when steps have been taken to reduce the amount of dust in the air. Sometimes, it can be difficult to reduce the amount of silica dust to levels below the permissible limits. A supplied air respirator may be needed for high levels of silica dust where water or ventilation can’t be used to control the dust. A supplied air respirator is required if the amount of silica in the air is more than 10 times the permissible limit”
Air-purifying respirator with dust cartridge
Supplied air respirator

34. Filtering Facepieces Air inhaled in Air inhaled in Air exhaled out
[optional slide] This picture shows how air moves in and out of the dust mask respirator with an exhalation valve. The act of breathing creates a negative pressure inside the mask, which is why these and dust masks are sometimes called “negative pressure respirators”. If the mask does not fit properly along the edges, contaminated air can enter. This is why fit-testing is essential when using dust mask respirators.
Dust masks will leak if they don’t fit your face properly. Dust masks don’t filter out chemical vapors. Dust masks are not adequate for heavy amounts of dust. Dust masks may not be suitable for highly toxic dusts
Air exhaled out

35. Assigned Protection Factor (APF)
Defined:
Workplace level of respiratory protection respirators are expected to provide when employer implements a continuing, effective respiratory protection program.
Respirators must be selected according to Assigned Protection Factors (APF)

36. Air Purifying Respirators
Half mask filtering facepiece Half mask elastomeric Full facepiece elastomeric APF = APF = APF = 50
Source: OSHA Small Entity Compliance Guide
Original Illustrations created by Attiliis & Associates

37. Air Purifying Respirators
Loose-Fitting Powered Loose-Fitting (Hooded) Powered Air-Purifying Respirator Air-Purifying Respirator (PAPR) APF = (PAPR) APF = 25/1000
Source: OSHA Small Entity Compliance Guide
Original Illustrations created by Attiliis & Associates

38. Air Purifying Respirators
Tight-Fitting Full Facepiece Tight-Fitting Half Facepiece Powered Air-Purifying Respirator Powered Air-Purifying Respirator (PAPR) APF = (PAPR) APF = 50
Often we hear the term hazard or hazardous and often the terms toxic and hazardous are used interchangeably. They are not the same!!
In the context of our discussion hazard is defined as UNCOVER AND READ.
When evaluation g a hazard, toxicity is but one factor to consider. How a chemical is used, where it is used, its physical properties (i.e.., vapor pressure, flammability), and warning properties such as odor must also be considered.
Lets look at an example evaluating the hazards of two chemicals using their warning proerties. GO TO EXAMPLE #1
Source: OSHA Small Entity Compliance Guide
Original Illustrations created by Attiliis & Associates

39. Respiratory Protection Program
Where respirators are required, you need:
Written program
Worksite-specific procedures
Required elements:
Training
Fit testing
Medical evaluations
Care and maintenance
Procedures for respirator selection
Procedures for routine & emergency use

40. Voluntary Use If employer permits voluntary use:
Provide information in Appendix D
Implement elements of written program necessary to ensure
Medical ability to use
Cleaned, stored, maintained to not cause health hazard
Exception: Voluntary use of dust masks

41. Respirator Training
Training is required for anyone who wears a respirator.
If you don’t know how to use a respirator properly, you may think your respirator is providing protection when it is not.
“ We will do respirator training for all of our employees who are required to wear respirators.” 27

42. Housekeeping
Dry sweeping is prohibited unless wet sweeping, HEPA-filtered vacuuming, or other methods are not feasible
Employer shall not allow compressed air to be used to clean clothing or surfaces unless:
Compressed air is used in conjunction with ventilation system
No alternative is feasible

43. Medical Surveillance Construction
Initial baseline examination must be made available for employees required by standard to use respirator for 30 or more days per year
No cost to employee
Reasonable time and place
Performed by PLHCP
Periodic examinations at least every three years