Silica- Clearing the Air

Scott Schneider, MS, CIHDirector of Occupational Safety and HealthLaborers’ Health and Safety Fund of North America

Silica is not a new problemIn 1700, Bernardino Ramazinni published a book on occupational diseases and recognized respiratory diseases among stone cuttersIn 1910, Alice Hamilton studied silica exposures among granite workers in VermontIn 1938, Congress was outraged when over 400 workers died of acute silicosis at the Gauley Bridge tunnel job in West Virginia

Francis Perkins 1938

Acting to “Stop Silicosis”

Francis Perkins, Secretary of Labor, in 1938 convened a National Conference to Stop SilicosisIn 1974, NIOSH recommends dramatic reductions in the silica exposure limit to 50 micrograms/cubic meter and a comprehensive standardRobert Reich, Secretary of Labor, in 1997, began a campaign with NIOSH “It’s Not Just Dust” and holds a National Conference to Eliminate SilicosisIn 2006, ACGIH recommends an even lower exposure limit, 25 micrograms/cubic meter

History of OSHA efforts

1974- OSHA publishes an “Advanced Notice of Proposed Rulemaking” on whether it should adopt the NIOSH recommended standard for silica (with 0.05 mg/m3 REL)1989- PEL Update- OSHA modernizes the PEL for Silica to mg/m3 but this rulemaking is thrown out by the courts1997- OSHA places silica standard on reg agenda as long term action1999- OSHA expects to propose a new silica standard by June 2000. Current PEL measurement method is labeled “obsolete”2003- OSHA completes Small Business panel review2010- OSHA completes Peer Review of Health Effects dataJune 2011- OSHA expects to publish Proposed Silica Standard

Health Effects of Silica

Reported deaths from silicosis have dropped to about 150 a yearBut many cases go unreported:

8.5% of NJ blue collar workers from dust-exposed industries who had underlying lung disease listed on their death certificate had undetected silicosis on autopsy

A Michigan study estimated about 3,600- 7,300 new cases of silicosis each year in the US

We have known for about 30 years that silica exposure also causes cancer

In 1997 IARC designated silica as a human carcinogen

Lung cancer from silica exposures probably outnumber silicosis cases

Silica causes other forms of respiratory disease as wellAwareness of the hazard is low because construction tends to be dusty and effects are chronic

Worksafe BC Video

Exposures and Controls

Silica exposures from construction operations can be very high, e.g. from tuck pointing and abrasive blastingBut exposures can be easily and inexpensively controlled using water or local exhaustMany studies have been published in the past 10 years showing 90- 98% exposure reductionMore tools are now coming equipped with controlsSome States (NJ, CA) have banned dry cutting and have not experienced any compliance problems

Dry Cutting is Risky Business

Wet vs. Dry Cutting

OSHA Publication on Controlling Silica in Construction - 2009

NIOSH Information products

Spanish versions

NIOSH engineering control page with control videos http://www.cdc.gov/niosh/topics/silica/constructionControlMain.html

Without dust controls

Dust suppression with water

Dust Control SolutionsSimple Solutions book from Arbouw in The Netherlands 2002•Includes criteria for purchasing equipment with controls

Dust Controls can help with productivity as well

The OSHA Proposal

The draft reviewed by SBREFA in 2003 contained the following elements: Lowered PEL- 3 choices Modernize measurement method from mppcf to

mg/m3 Table 1 specifies controls for high exposure tasks These elements have been designed specifically

to make it easy for small businesses so they don’t have to do a lot of expensive air monitoring

Table 1- Required Controls

It’s About Time

Silica has long been a health problem in constructionThe Government has been trying to regulate it for almost 30 yearsThere are easy and inexpensive controls availableIt’s finally time to get to work and protect workers from this serious hazard