THE COHEN GROUP
  Environmental Health & Safety Consulting Services

The Cohen Group Newsletter - Volume 8  Issue 2, Article 4.  May, 2006

Silica remains a topic of interest to many. Here is a brief run-down on the latest, as we’ve been able to determine.

OSHA: Silica remains high on OSHA's regulatory agenda, but the Agency did not take action in April as originally scheduled. It is our understanding that OSHA has set a new deadline of November to complete peer review of a health effects and risk assessment document.  Our impression is that it is unlikely anything will happen soon.

Cal/OSHA: No discussion of a change. The current PELs are: 0.05 mg/m³ for Cristobalite (respirable dust); 0.1 mg/m³ and 0.3 mg/m³ for Quartz (respirable and total, respectively). There are additional PELs for other crystalline forms.

ACGIH: The American Conference of Governmental Industrial Hygienists (ACGIH) has adopted the proposed lowering of its Threshold Limit Values (TLVs) on Crystalline Silica, to 0.025 mg/m³ (respirable particulate mass) as an 8-hour, time-weighted average. Previously, the TLV was 0.05 mg/m³. ACGIH included Cristobalite as part of its revised TLV and now identifies these silica forms as an A2, Suspected Human Carcinogen.

MSHA: The Agency has stated it may seek information on respirable Crystalline Silica for the purposes of establishing a standard; however, no timetable has been offered.  "MSHA is considering several options to reduce miners' exposure to crystalline silica," the Agency said. 

OEHHA: Not much activity of late, but at a November 2004 meeting, this lead agency for Prop 65 adopted a Chronic Reference Exposure level for Crystalline Silica of 0.003 mg/m³ (or 3 µg/m³). OEHHA is mandated to develop risk assessment guidelines to be used by state and local agencies in implementing the Air Toxic Hot Spots program. In November 2003, this same agency issued a safe use determination at the request of the National Paint and Coating Association for Crystalline Silica used in interior flat latex paints containing no more than 6% crystalline silica (with diatomaceous earth as the sole source of crystalline silica).