Aberrant Antimony

Antimony is emerging from the heap of toxic metals. Its past uses have been infrequent and overshadowed by lead, but “times are a’ changing” as technology forages into the future.

Historically, antimony has experienced a very curious narrative.  Stories excerpted from the National Institute for Occupational Safety and Health (NIOSH) follow:[1]

• In 4000 BC, antimony was used in the manufacture of vases and vessels—no records of adverse effects to the workers.
• About 2000 BC, Egyptians used antimony sulfide in cosmetics to be used as black eyeliner.
• Around 70 AD, the Roman Herbalist and Father of Pharmacy, Pedanius Dioscorides, prescribed antimony as a medicine. The Romans were known to use antimony as an emetic to induce purging (e.g., induce vomiting).
• In 1713, the Italian physician and forerunner of occupational medicine Bernardino Ramazzini  recorded: (1) a chemist exposed to antimony fumes was tormented by a cough which the chemist thought was related to acid vapors; and (2) glass makers suffered vertigo, ulcers in the mouth, esophagus, and trachea, and “consumption” (e.g., body wasting).
• In the early 1900s, typesetter disorders were associated with molten antimony.  The disorders included weakness, intense depression, pallor, palsy-like tremors, bladder and urination pain, temporary impotence (e.g., infertility), dyspnea (e.g., shortness of breath), irritable hyperactivity of the heart, and gastric irritation.  Although lead and arsenic components were likely impurities in the antimony, symptoms were not that of lead intoxication.
• Also in the early 1900s, antimony salts (e.g., antimony potassium tartrate and antimony sulfide) used as color fixatives in clothes dyes and in foundries were linked to necrotic dermatitis and scarring.  Antimony was being used to treat tropical diseases as well.

Today, powdery antimony trioxide is primarily used as a flame retardant. As a fire retardant additive, it is not as likely to pose an airborne toxics hazard. However, there are those who would suggest that sudden infant death syndrome may be related to antimony powder leaching from infant flame retardant mattresses.  Other antimony-containing flame retards are used in toys and children’s clothing and in automotive/aircraft seat covers.  Antimony trioxide has also been used in fiberglass resins for light weight, flame retardant aircraft “engine covers.”

The elemental metallic antimony is used in anti-friction alloys (often referred to as Babbitt metal).  Antimony increases hardness and mechanical strength. High temperatures are required to melt metals and turn them into liquids. As metals melt, fumes may or may not be visually apparent (e.g., smoke).  Some other manufacturing processes likely to involve antimony are: (1) lead-acid batteries (Pb-Sb), (2) bullets/lead shot, (3) linotype printing machines, (4) lead-free solder, pewter, and (5) the manufacturing of organ pipes. Antimony is increasingly being used in the semiconductor industry as a dopant to increase processing speed, and it is used in medicine, cosmetics, safety matches, paint, and bubble-free glass.

So, where does this lead us? Sauntering down the road to occupational exposures—elemental antimony, antimony oxides, and antimony sulfides have variant uses and health effects. These aberrations are truly phenomenal.

• Elemental Antimony—silver-colored metal                                                                                                                                                               Elemental antimony is used as a metal alloy and is an irritant of the mucous membranes, eyes, and skin.       

• Antimony Oxides (trioxide and pentoxides)—white powder                                                                                                                                             Antimony trioxide is a flame retardant and causes pulmonary injury. It is also a suspect carcinogen.

• Antimony Sulfides (trisulfide and pentasulfide)—dark gray powder                                                                                                                            Antimony trisulfide is used in fire works and is cardiotoxic.

In brief, the basic use differences are metal alloy verses flame retardant verses pyrotechnics, and the health impact differences are irritation verses pulmonary injury verses heart damage. There have been multiple studies that indicate greater health hazards than those posed herein. Yet, clearly there are aberrant uses and aberrant health effects in the Wild World of Antimony.

Relegated to the back seat of lead and chromium, antimony and antimony compounds pose a threat that is all too often ignored in industry.  Heads up!