Health Hazards Those hazards which may cause measurable

Health Hazards Those hazards which may cause measurable changes in the body or its functions

Hazards § Physical § Chemical § Biological § Ergonomic § Psychosocial § Other(surfaces, flammables, heights, tips)

CHEMICAL HAZARD H. R. Sarreshtahdar, MD Occupational Medicine Specialist

Chemical hazards ◦ Chemicals are the most common and significant health hazards ◦ Chemicals can be hazardous for numerous reasons and can combine with other chemicals to make new hazards

Toxicity Ability of the substance to harm the body The dose makes the poison Depends on : Amount + Duration Toxicity

Hazardous Chemical Substances Entail a risk due to: ◦ Its toxicological properties ◦ Its temperature ◦ Its radioactivity ◦ Displacement of atmospheric oxygen ◦ Increase the risk of fire, explosion, …

Classification Carcinogenic Irritant Corrosive Sensitizing Reproductive Genotoxic Asphyxiants toxin

Carcinogenic IARC Group 1 (carcinogenic) ◦ Benzene, PAH, asbestos, silica Group 2 A (probably carcinogenic) ◦ Acrylonytrile, vinyl chloride Group 2 B (possibly carcinogenic) ◦ Acrylamide, lead, chloroform Group 3 (not classifiable) Group 4 (probably non-carcinogenic)

Irritant Causes a REVERSIBLE inflammatory effect on living tissue by chemical action at the site of contact ◦ Formaldehyde, most solvents

Corrosive Causes visible Destruction of or IRREVISBLE alterations in living tissue by chemical action at the site of contact ◦ Phenol, acids and bases

Sensitizer Causes a substantial portion of exposed people to develop an Allergic reaction in normal tissue after repeated exposure to the chemical Nickel,

Target Organ Classification Neuro-toxic Cardio-toxic Hepato-toxic Nephro-toxic Hemato-toxic Reproductive toxin Oculo-toxic Oto-toxic Pulmonary toxin Vasculo-toxic Dermato-toxic Immuno-toxic

Physical Properties Aerosols: ◦ ◦ Dust Fumes Smoke Fiber Gases and vapors Fluids

Combined effects of chemicals Independent Additive Antagonistic Potentiating Synergistic

Routes of Exposure & Absorption Inhalation

Routes of Exposure & Absorption Skin/eye contacts

Routes of Exposure & Absorption Ingestion

Particulate Sizing Inhalable Particle Mass Thoracic Particle Mass Respirable Particle Mass

Factors affect toxicity Physical state Chemical structure Duration of exposure Frequency Route Intensity Environmental (temp/humidity/pressure) Individual factors ◦ race/genetics/immune/nutrition/activity/stress/ background disease

Monitoring Environmental Biological monitoring

MSDS Prepared by the chemical manufacturer or importer and describe: ◦ Physical hazards, such as fire and explosion ◦ Health hazards, such as signs of exposure ◦ Routes of exposure ◦ Precautions for safe handling and use ◦ Emergency and first-aid procedures ◦ Control measures

MSDS Must provide information about the: ◦ Physical and chemical characteristics ◦ Health effects ◦ Exposure limits ◦ Carcinogenicity (cancer-causing)

Toxicity Information of the potential health hazards of chemicals is derived from. . . 1) Toxicological studies (in vivo, in vitro) 2) Case reports 3) Epidemiological studies

Acute toxicity Acute oral, dermal or inhalation toxicity Provides information on acute health hazards likely to arise from acute exposure to the substance by the given route, and on the magnitude of acute toxicity of the substance usually these tests are made with rodents, dermal test quite often with rabbits LD 50/LC 50 values (dose level which is caused death to 50% of animals)

Dose-response relationship: lead decreased erythrocyte delta-ALAD activity increased zinc protoporphyrin anemia CNS effects decreased peripheral nerve conductivity Nervous paralysis, lead colics Adapted from Elinder C-G et al. , Biologisk monitoring av metaller hos människa. Arbetsmiljöfonden, Uppsala, 1991