Silica 411 Assessing Silica Risk Rick Supples Applied Improvement Technologies

Learning Objectives Learning Objectives At the end of this presentation you will be able to: State the difference between silicon, silica, silicates and silicone. State the difference between crystalline and amorphous forms of silica. Describe Health Risk Recall legacy exposure event Describe at-risk occupations Describe the OSHA Permissible Exposure Limit and ACGIH TLV Describe exposure control methods Describe silica risks for home DIY projects When John asked invited me to present a topic, after I got off p[hone I just realized, I’m presenting to the experts like Ann Bracker and John Able who know more about silica than I ever will So thank you John for your graciousness Disclaimer - I am not an expert on silica – I will discuss from a practitioner point of view We do silica exposure assessment, mostly in gen industry but some construction work This is meant to be a primer – clearly not a deep dive If you’re a rock collector – you’ll love these slides There’s excellent primer information on silica. OSHA has taken the lead in communicating silica risk to industry. If I had to choose the best, well-communicated, rich with learning aids standard, Silica would be one of my top 3

1. Differences: Silicon, Silica, Silicates and Silicone? Silica Terminology 1. Differences: Silicon, Silica, Silicates and Silicone? There’s a lot of terms floating around when it comes to silica LOT’s of misunderstanding We need to define some basic terms

Silicon is an element (Si) Commercially obtained from sand Combines with O2 forms molecule (SiO2) = silicon dioxide = silica Forms rocks = silicates There’s so much O2 that it rare to find pure silicon because it bounds with O2.

What happens to silica in nature? silica + mineral + time = other silicates Remember I said if you’re a rock collector you’ll love this We’re surrounded by silicates Difficult to extract any mineral deposit from the earth that doesn't contain silica

2. Crystalline vs. Amorphous Silica

What’s the difference between crystalline and amorphous silica? Crystalline silica is quartz, also found in pottery, ceramics, bricks, concrete and artificial stone Amorphous = non crystalline It’s the crystalline form that presents a health hazard to human lungs Amorphous silica = not-crystalline silica Amorphous silica includes glass, flint, opal,  silica gel

3. Health Risk & Disease Silica disease has been around since ancient Greeks described it

What is the risk from rocks? Quartz is most common form of crystalline silica. Quartz close cousins - cristobalite & tridymite Hard to extract anything from earth that is silica-free All three forms may become respirable size dusts if work involves chipping, cutting, drilling, or grinding objects that contain crystalline silica. We can have a piece of pure silica quartz for the rest of our lives and never have a problem But if apply some mechanical process to decrease particle size …. wammo

Are all dust sizes created equal? 3 dust categories Inhalable (  100 µm) Thoracic (  10 µm) Respirable (  4 µm) Most important slide – if you forget everything else remember this slide. Inhalable particles are big (100 microns – you can see them in the air - sneeze on airplane) If you breathe in an inhalable particle – it will get stopped by your nose and throat filters Thoracic particles will get stopped in the throat/larynx area But respirable particles are the concern – these are 4 microns and stay in the air a long time and get down to alveoli where oxygen goes into your blood the size of one blood cell Respirable are about 100 times smaller than a sand particle

Disease Types Silicosis (Proliferative Pneumoconiosis) Lung Cancer Chronic obstructive pulmonary disease (COPD) Kidney disease Just want to dip a little bit into silica disease Pneumoconiosis = Group of Lung diseases caused by dust exposure This is important – no airborne dust = no exposure =no disease Proliferative Pneumoconioses freak us out in our profession Disease progresses after exposure! What’s the classic example of Prolif Pneumo?

Dusty Lung Diseases Proliferative Non-Proliferative Silicosis White lung disease Black lung disease Shaver’s disease Non-Proliferative Talcosis Stannosis Siderosis I used an archaic term - white lung disease Dusty lung diseases comes in two types – Proliferative vs Non-Proliferative Any guesses on what proliferative vs non-proliferative disease means? This is the tragedy/curse of silicosis – even after exposure stops = disease progresses

Why Recent Compliance Focus? Debilitating disease Exposure is common 2 million U.S. workers currently exposed (NIOSH) The Silica standard IMHO is one of the best standards in terms of outreach and communication to industry.

4. Legacy Exposure Event

1930 hydroelectric project 3 mile tunnel was cut through Gauley Mountain – high granite 2,500 workers, drilling through high concentrations of silica rock No PPE Tunnel Rock Composition – commercial value for steel production Tunnel diameter was expanded to offset the cost of the project. Every once in awhile legacy ASP/CSP exam - Gauley Bridge Tunnel Project began Engineers realized silica had commercial value for steel production

5. At Risk Occupations

Construction OSHA estimates 2.3 million U.S. workers potentially exposed to crystalline silica ~90% of those workers employed in the construction industry. Construction Jobs: Masonry saws, grinders, drills, jackhammers, chipping tools Operating vehicle-mounted drilling rigs; milling; operating crushing machines Operating heavy equipment for demolition Focus is on construction industry – ESPECIALLY DEMOLITION General industry and maritime – employers have until June 23, 2018

General Industry Concrete products, foundries Hydraulic fracturing for gas and oil Dental laboratories Abrasive blasting Not much concrete mfg or foundries left Some fracturing Lot’s of dental labs Casting –mixing casting materials and during divestment of castings. Sandblasting – Sandblasting of castings Grinding porcelain – Silica content in porcelain varies. Lots of abrasive blasting in mfg

Foundry

6. Exposure Control Methods

Hierarchy of Controls ESEAP Here’s another CSP tip. Lots of Many of the exam questions ask how we control risk for our employees – I made up this memory trick – in order of priority

Elimination Substitution Engineering Administrative PPE Elimination is difficult in construction/demolition work – cuz workers are taking away the old material Substitution very important in sandblasting Engineering controls very important in construction – what are they? Famous Table 1 takes

Sandblasting Has anyone ever seen sandblasting before, say on a bridge or municipal project? Use of silica sand is not prohibited in the US, but other substitutes are available Risks when any type of abrasive blasting is not only the media used, but the substrate material being removed Tough trade - High noise and dust risk Silica sand still in use

Exposure Control - Sandblasting Substitution to non-silica abrasive critical Employers find change difficult Non-silica abrasives are more effective and less costly The only people that like change are wet babies

Silica Substitutes Metal Surface Treatment – Deburring - Paint Removal Aluminum Oxide Glass Bead Steel Shot Baking Soda Metal Slag Corn Cob Granules Peach Pits Nut Shells Dry Ice Plastic Media These same substitutes can be used in Manufacturing or Gen Industry= When we’re talking about silica in Gen Industry = usually involves Grit Blasting Cabinet

7. New Rule Highlights Small-business employers can use specified dust control methods in lieu of sampling Must have a written exposure plan (ECP) Must define housekeeping practices Must offer medical exams Must train workers Must keep records New rule is actually two new standards, 1 for construction and the other for general industry/maritime.  29 CFR 1926.1153 and 1910.1153 Housekeeping - Dry sweeping or brushing should be avoided if feasible. Use a HEPA-filtered vacuum or wet sweeping to clean up debris. There’s overlap in requirements including these:

Silica Control - Construction Option A Option B Use Table 1 Tools with ventilation or water systems built-in. Best method for construction takes guesswork out Performance-oriented option or Scheduled monitoring option Measure workers’ exposure to silica, choose dust controls to limit exposures to < PEL Scheduled sampling =quantitative measurements 2 trigger levels - above the permissible exposure limit (PEL) and action level (AL). Use “if/then” guide detailing the sampling schedule Performance Option - it’s complicated!

Table 1 Specified Exposure Control Methods When Working With Materials Containing Crystalline Silica If you’re in the construction world – you know about Table 1. Great piece of work by OSHA Must have tools if doing demolition work Table 1 takes guesswork out of the equation for tool use Good News - OSHA is working on expanding Table 1 to include more tool types When you think of Engineering controls – what are we usually talking about? Ventilation & wet methods Some construction will need to upgrade tools or purchase shrouds and dust collection system

We sampled a demolition job in summer Work crew was dismantling portion of building Hot ambient summer temperatures Some years ago we sampled a demolition job Employees were cutting through concrete floors – since AC was off and internal ambient temps > 90 F Using large pedestal fans to cool themselves

8. Occupational Exposure Limits There are 2 commonly used OEL’s for silica One is the law of the land The other is based on best available science

How is respirable dust measured? Anyone ever used this device for silica? Since we’re interested in respirable silica particles, we want a device that selects only 4 micron Here’s a device called a cyclone that collects respirable size particles, it doesn’t know if the particles are silica or not. Tedious to sample with Periodically pull off cap and clean with alcohol

What’s the Risk for a DIY’er Masonry saws, grinders, jackhammers, or handheld chipping tools If you’re a weekend warrior and like to do your own remodeling/renovation..go to Home Depot or Lowes…. You can rent any one of these tools – water to control dust Home Depot – You can do it, we can help, My home depot - You can’t do it, and we won’t help.

So what about silicone?

Thanks for coming!