CHEMICAL HAZARD AND PREVENTION FIRDAUS ALI BSc (Health and Safety), Curtin University, Perth Australia
Objectives of this session • Understand the key definitions and fundamental concepts of chemical hazards • Identification of chemical hazard and route of exposure • Describe the worksite assessment process • Identify the hierarchy of control measures
Key Definitions Hazard A situation that poses a level of threat to life, health, property or environment Risk The chance of something happening that will have an impact on life, health, property or environment (AS/NZS 4360:2004)
Exposure Defined as the contact over time and space between a person and one or more biological, chemical or physical agents based on frequency, magnitude and duration (US Nuclear Regulatory Commission, 1991).
Toxicology Defined as the study of adverse, and potentially adverse, effects of chemicals which have, or may have, the capacity to cause injury to living organisms.
"Dosisfacitvenenum" - The Dose Makes the Poison All substances are poisons; there is none which is not a poison. The right dose differentiates a poison…." Paracelsus (1493-1541)
Dose The dose of a hazardous substance is generally expressed with the following equation: Dose = concentration (level) x durationof exposure. This is a fundamental principle on which occupational exposure limits (OELs) are based
Toxicity Refers to its capacity to injure if it reaches a susceptible site on the body. Whether ill-effects will occur depends on: • The properties of the chemical • The dose (amount of chemical acting on the body) • The susceptibility or resistance of the exposed individual • The route by which the substance enters the body
Identification of Chemical Hazard Substances which can be inhaled, or are respirable, include gases, vapours and aerosols, may be defined as follows: • GASES: substances which normally exist in gaseous form at standard pressure and temperature • VAPOURS: the gaseous form of substances normally liquid at standard pressure and temperature • AEROSOLS: suspensions of variable size particles capable of remaining airborne
Dusts – caused by mechanical abrasion or fragmentation of solids • Fumes – produced by combustion, sublimation or condensation of volatile solids. • Smokes – suspension of solid particles produced by incomplete combustion of organic materials • Mists – airborne droplets usually formed by condensation of vapours but may be produced by atomisation of a liquid
Chemicals That Present Hazard or Risk • Flammability: catch fire readily; gasoline • Reactivity: unstable and may explode or create toxic fumes when mixed with water; explosives, concentrated sulfuric acid • Toxicity: injurious to health; pesticides, chlorine
Material Safety Datasheets A document containing important information about a hazardous chemical (which may be hazardous substance and/or dangerous goods) and must state: • a hazardous substance's product name • the chemical and generic name of certain ingredients • the chemical and physical properties of the hazardous substance • health hazard information • precautions for safe use and handling
Chemical Groups International Version published by the WHO and European Union Available at: http://www.ilo.org
Safety Label Available at: http://www.cdc.gov/niosh
Legislation on Chemical Safety • Poison Act, 1956 • Disaster Management Order, 2006 • Workplace Safety and Health Order, 2009 Available at: http://www.agc.gov.bn
The Respiratory System A large range of vapours and gases, dusts, fumes can enter the respiratory tract through inhalation • Odours - danger lies in using chemicals which have no odour, or where toxicity occurs before odour is detected. People who have had a long term exposure to a chemical tend to ignore the smell • Dusts - Many dust particles are small enough to enter the alveoli air pockets where they can cause damage
The Skin The protective properties of the skin can be reduced by exposure to chemicals such as degreasers, detergents, and solvents • Chemical exposure can result in dryness, splitting and cracking and damage to the skin surface • Sensitivity to chemicals can cause allergic reactions - in rare circumstances can cause death
The Eyes • Some chemicals have very strong vapours that can cause acute discomfort to the eyes. • Exposure to these types of fumes can cause permanent damage to the eyes. • Care must be taken to protect from splashes as well as fumes
The Gastro - Intestinal Tract • Usually due to poor housekeeping, dusty environments and the close proximity of toxic airborne substances to eating facilities. • Poor hygiene practices (not washing hands before eating & not wearing gloves when dealing with chemical) can also prove hazardous
Potential Chronic Health Problems • Occupational Asthma (Glutaraldehyde) • Carcinogen (Ethylene oxide and Cyctotoxic Drugs) • Kidney Failure (Lead fumes) • Lung Fibrosis (Diesel) ?
Direct health indicators (worker complaints, illness statistics, biological or radiological signs before symptoms occur) • Previous experience and information (MSDS, material inputs, the process, the pattern of exposure, work procedures) • Walk-through survey (5 P’s; People, Premises, Process, Product, Personal Protective Equipment) • Specific Site • Specific Task
Risk Assessment Systematic process for describing and quantifying the risks associated with hazards including substances, processes, action or events.
The overall process of risk identification, risk analysis and risk evaluation (AS/NZS 4360:2004).
Chemical handling on Glutaraldehyde (Cidex) for disinfecting endoscopy and operating theatre instruments
Control measures 5 steps of hierarchy of control measures • Elimination (Remove) • Substitution (Replace) • Engineering Control (Remodel/Renovate) • Administrative/Procedural Control (Reinforce) • Personal Protective Equipment (last Resort)
Elimination Depends! -Detrimental effect on human body -Demand of the product • Substitution -Replace with a less hazardous substance
Engineering Control -Fume Cupboard (Grading for different types of chemical handling/performance) -Ventilated room with back vent • Administrative/Procedural Control -Education and Training -Legislation -Standard Safety Procedure (Chemical Handling) -MSDS -Incident Report -Regular medical checkup
Personal Protective Equipment Different types of chemical have different use on each equipment -Hand Gloves -Face Guard/Mask -Safety Apron/Safety Suit -Rubber Boots -Helmet ?
SCENARIO You as an Occupational Health Nurse have been advised to investigate an incident in the endoscopy unit. It was reported that 10 healthcare workers have been suffering from acute exacerbation of asthma for 3 days. It was later identified that all affected HCWs were handling Glutaraldehyde (Cidex) while disinfecting endoscopic instruments. (a) Describe how would you perform a worksite assessment. (b) Using the hierarchy of control measures, provide recommendation in order to minimise the health impact of Glutaraldehyde (Cidex)
WORKSITE ASSESSMENT Walk through Survey 5 P’s (People, Premise, Process and Product, Personal Protective Equipment) Specific Site Specific Task (the pattern of exposure, work procedures)
Substitution Replace Glutaraldehyde with a less toxic substance. • Engineering Controls Provide local exhaust ventilation such as laboratory hood, large enough to contain the Glutaraldehyde immersion system and an equipment washing and rising sink at the source. The design should include a face velocity at the hood with the airflow directed toward the back of the hood away from the operator’s breathing zone. This system will require an appropriate amount of filtered and tempered replacement air in order to work properly Increase general room ventilation. This solution is generally ineffective in controlling exposure due to short-term tasks such as equipment cleaning or solution changes that may generate a high concentration contaminant quickly
Provide buckets and other containers that are shaped to minimise the surface area of the liquid. Modify facility design to limit traffic or potential exposure to individuals who are not involved with the disinfection process. Exposure to Glutaraldehyde solutions in confined spaces should be avoided
Administrative controls Reviewing work practices periodically in all areas where Glutaraldehyde is used in order to prevent overexposure. Communicate with other areas of the hospital setting that use Glutaraldehyde such as surgical department, emergency rooms, intensive care unit or central sterile supply department Training and educating new and current healthcare workers regarding safe work practices is essential in reducing chemical exposure. All new and current healthcare workers should be instructed about the potential hazards associated with Glutaraldehyde, proper use of protective clothing, safe work practices, avoidance of exposure in a confined space and personal hygiene concerns. This would include education regarding signs and symptoms associated with overexposure to Glutaraldehyde
Personal protective equipment A written procedure detailing the type of clothing and the proper use of protective clothing should be provided to healthcare workers involved in maintenance and disinfecting medical instruments. Proper gloves wear such as butyl rubber, polyurethane or Viton could be use Respirators or face mask are necessary when the exposure to a chemical exceeds 0.1ppm. Nevertheless, this should be known not as a primary control since the availability of engineering control and substitution of chemical. Yet, this can still be use in non routine maintenance or emergencies (NIOSH, 2005).
Further Information • http://www.worksafe.vic.gov.au • http://www.westcoastdhb.org.nz • http://www.ilo.org • http://www.cdc.gov/niosh • http://toxnet.nlm.nih.gov/