Control Banding:Getting from Here to There St. Louis Safety Council – St. Louis October 20, 2010 Thomas Kibby, MD MPH BJC Corporate Health Services
Control Banding - Definitions • A method of linking control methods to the hazard assessment of the materials handled (AIHA)… “an evolving strategy” • A process in which a single control technology is applied to one range or band of exposures to a chemical that falls within a given hazard group (NIOSH)
“My company doesn’t have the money to take air samples for all the chemicals used in our plant. Many of these chemicals don’t have permissible exposure limits. How do I know which tasks in my facility may need controls?”
Why Use Control Bands? • Not needed if already use an OEL and specific IH monitoring to the control technology. • But most of our products do not have the luxury of OEL’s, IH methods and validated control technologies. • Control banding gets the IH from here to there
Health Hazard Control Band 1 Risk Assessment 2 3 4 Exposure Potential Quantity Airborne Tendency
Assumptions • Most substances can be grouped into health hazard bands, such as four categories of increasing toxicity. • Each band can be assigned a target maximum exposure that should not be exceeded. • Exposures are primarily a function of quantity, dustiness (or volatility), and the level of control. • Most manufacturing facilities use similar unit operations (e.g., bag filling, mixing, material transfer). • A combination of unit operation and exposure control can be recommended so that the target maximum exposure is not exceeded.
Hazard Assessment Assign to highest Category that pertains: • Skin or respiratory irritant • Harmful on single exposure • Very Toxic on single exposure; Severely irritating & corrosive; or a skin sensitizer • Very toxic on single exposure; or a reproductive hazard; carcinogens, asthmagens
Exposure Assessment Combined judgment based on • Quantity used • Tendency to become airborne
Match to Control Strategy • Use good industrial hygiene practice and general ventilation. • Use local exhaust ventilation. • Enclose the process. • Seek expert advice
History of Control Banding • 1980’s: Pharmaceutical benchmarking of Tox, IH and Medical (OTR) begins meeting • 1988: OTR develops concept of Category Band; all participants develop own CB but not uniform • Late 1990’s: UK HSE develops COSHH Essentials • 2000’s: UN-WHO and Canada develop own versions
Why Did Pharma Start Banding? • Many potent compounds: • highly active pharmaceuticals: API • chemotherapy, hormones with occ exposures • Many unknown compounds: • R&D environment • isolated process intermediates (IPI) • Standard processes: • bulk quantities of powders, fine particle size
Generic Control Band Scheme From NIOSH Safety and Health Topic: Control Banding
COSHH Enhancements UK’s Health and Safety Executive (HSE) Control of Substances Hazardous to Health (COSHH) regulations Applies to materials identified as “dangerous for health” as listed by: Supplier for the material Regulation: CHIP Approved Supply List Substances with Workplace Exposure Limits
COSHH Essentials Steps • Assess the hazard (toxicity) • Assess dispersal potential • Dustiness for solids • Volatility for liquids • Determine amount in use • Above will determine process controls
Step 1: Hazard Assessment MSDS Risk phrases: A classification number and a description of the level of the danger is allocated to the chemical according to set rules. This is called a "Risk phrase" or "R-phrase".There are three levels of danger: • "harmful" • "toxic" • "very toxic" - being the most dangerous.
Risk Phrase Examples • R20 Harmful by inhalation • R20/21 Harmful by inhalation and in contact with skin • R20/21/22 Harmful by inhalation, in contact with skin and if swallowed • R20/22 Harmful by inhalation and if swallowed • R21 Harmful in contact with skin • R21/22 Harmful in contact with skin and if swallowed • R22 Harmful if swallowed • R23 Toxic by inhalation • R23/24 Toxic by inhalation and in contact with skin • (61 total health phrases)
Hazard GroupsHuman Health Effects • A Irritant • B Harmful on single exposure • C Toxic, corrosive, etc; skin sensitizer • D Very toxic, toxic to reproduction • E No health-based limit: Asthma, cancer, genetic damage • S Special conditions
Linkage R-Phrase Hazard Group Max. Airborne Conc.
Dust mg/m3 A 1 - 10 B 0.1 - 1 C 0.01 – 0.1 D <0.01 E seek specialist advice S N/A Vapor ppm A 50 - 500 B 5 - 50 C 0.5 - 5 D <0.5 E seek specialist advice S N/A COSHH Hazard GroupsAirborne Concentration Range
Step 2: Exposure Potential • Tendency to Go Airborne • Solids: dustiness potential • Liquids: volatility • Scale of Use • Volumes handled
Low Medium High Pellet-like solids PVC pellets, waxes Crystalline, granular solids soap powder, sugar Fine, light powders cement, titanium dioxide Dustiness Potential
Small volumes Medium volumes Large volumes milligrams/milliliters kilograms tons or cubic meters Scale of Use
Step 3: Controls Strategies • CS1: general ventilation • CS2: engineering control • CS3: containment • CS4: expert advice
COSHH Worked Example TOUGH LACQUER CO manufactures lacquers.They buy liquid Citox from their supplier in drums. They transfer it from the drum in a batch process to a reactor containing resins where it gets mixed to make lacquers. They do this twice a day for a period of 2 hours each batch.
MSDS for Citox • Section 9 Chemical & physical properties • Physical state: Liquid at normal temperatures • Boiling point: 134°C; Flashpoint: 36°C • Flammability limits: 2.3-6.6% • Section 15 Regulatory hazard information • R10 (flammable) • R21/22 (harmful in contact with skin or if swallowed) • R36/37/38 (irritating to eyes, respiratory system of skin)
Volatility • Citox is a liquid and the Tough Lacquer Co now needs to say how volatile this is. Section 9 of the safety data sheet says that citox has a boiling point of 134 ºC This is shown on the screen.If the vapor pressure has been given (it wasn't) this could have been entered instead of the boiling point. If using vapor pressure the Tough Lacquer Co would have needed to check they were entering the right units.
Operating conditions • Twice a day, for each batch, the Tough Lacquer Co add 50 - 100 liters of citox to the reactor over a period of 120 minutes. Because they are using liters of the chemical they are using a medium quantity.All this information is now entered on the screen.
Summary of COSHH Advice COSHH Essentials allocates control approach 'Containment' to transferring Citox, available as PDF files. COSHH Essentials recommends 7 control guidance sheets, • G300 gives general advice • 4 for specific transferring tasks, (the Tough Lacquer Co consider G306 is most relevant to them) • 2 on skin protection.
Is e-COSHH Validated? • During drafting, substances with accepted OEL’s and control measures were used as a reference point • Field studies have shown good but not perfect controls using materials with established OEL’s.
Limit of COSHH Essentials • Not suitable for gases • Does not address by-products or substances generated by the process • Does not address safety or environmental risks (e.g. flammability) • R-phrases not available outside of EU • Still needs “reality check” • http://www.coshh-essentials.org.uk/
ILO Chemical Control Toolkit • Developed for • Small to Medium Enterprises (SME’s) • Developing countries • Like COSHH but • Uses R-phrase and GHS system on MSDS, so user judgment needed to assign hazard band • Somewhat larger margin of safety