OSHA Radiation Regulations

Exposure to some forms of radiation is inevitable. Sunlight, for example, is radiation. So are the invisible radio waves passing through the air at all times and the fields surrounding high-frequency power lines. But some forms of radiation are particularly dangerous and a threat to workers. OSHA regulates these situations carefully with precise definitions on the amount and type of radiation to which employees can be lawfully exposed.

Types

• The OSHA radiation regulations are divided according to two types of radiation. Ionizing radiation, the more dangerous variety, is strong enough to remove electrons from molecules by which it passes. Sources of ionizing radiation include X-ray devices, particle accelerators and the sun. Nonionizing radiation sources include radio waves, electrical cables, electronic devices, microwaves and visible light.

Features

• OSHA standards for exposure to ionizing radiation are measured in doses of roentgens, rads and rems as they relate to absorption by the human body. One roentgen (R) is the amount of radiation needed to free one electrostatic unit of charge (esu) in 1 cubic centimeter of dry air at standard temperature and pressure. A rad is equal to the amount of radiation resulting in absorption of 100 ergs (10,000 nanojoules) per gram of body tissue. A rem is used to quantify absorption of various radiation sources in relation to one R of X- or gamma (solar) radiation.

Exposure

• According to OSHA regulations, no employer can allow an employee to be exposed to sources of ionizing radiation in any way that will cause them to be exposed to 1.4 rems per calendar quarter to their head and trunk, active blood-forming organs, lens of eyes or gonads. For exposure to strictly the hands and forearms or feet and ankles, the limit is 18.75 rems per quarter. Exposure to the skin of the whole body is limited to 7.5 rems per quarter.

Signs

• OSHA defines a radiation area as any place accessible to employees where radiation exists at levels that could cause absorption of 5 millirems or more in a single hour or 100 millirems in five consecutive days. Such areas must be conspicuously marked with a sign in the conventional radiation caution colors (magenta or purple on yellow) and the words "Caution Radiation Area." A high-radiation area is any where a dose in excess of 100 millirems could be absorbed in a single hour. Such areas must be marked with a sign bearing the words "Caution High Radiation Area."

Nonionizing Radiation

• OSHA does not maintain specific standards for exposure to the various forms of nonionizing radiation that can result in the workplace. However, employers are bound by Section 5(a)(1) of the OSH Act that requires them to provide workplaces that are free of known hazards likely to cause death or serious harm.