Labeling of Chemicals has designated the following hazards for exposure to chloroprene: flammable, toxic, dangerous to the environment, health hazard and irritant. Chloroprene poses fire hazard (flash point ). OSHA identifies chloroprene as a category 2 flammable liquid and emphasizes that at least one portable fire extinguisher should be within 10 and no more than 25 feet away from the flammable liquid storage area. OSHA provides resources on addressing flammable liquids at industrial plants which is where the likely exposure to chloroprene exists (see external resources). As a vapor, chloroprene is heavier than air. According to the National Fire Protection Association's rating system, chloroprene is designated with a category 2 health hazard (temporary incapacitation or residual injury), a category 3 fire hazard (ignition under the presence of moderate heat), and a category 1 reactivity (unstable at high temperatures and pressures). Chronic exposure to chloroprene may have the following symptoms: liver function abnormalities, disorders of the cardiovascular system, and depression of the immune system. The Environmental Protection Agency designated chloroprene as likely to be carcinogenic to humans based on evidence from studies that showed a statistically significant association between occupational chloroprene exposure and the risk of lung cancer. As early as 1975, NIOSH had identified the potential health hazards of chloroprene in their bulletin primarily citing two Russian cohort studies from those working with chloroprene in an occupational setting. Hazard controls Several epidemiological studies and toxicological reports provide evidence of chloroprene's capability to inflict occupational health and safety concerns. However, varying reviews of the degree to which chloroprene should be held responsible for health concerns highlight the criticality of sound scientific research. Only one fatality as a result of chloroprene intoxication has been recorded which was a result of cleaning a container used for chloroprene. The primary occupational concern for chloroprene is limited to the facilities producing chloroprene and using chloroprene to produce the synthetic rubber, polychloroprene. NIOSH developed a list of actions to address specific workplace hazards. These actions are represented in their diagram of the "Hierarchy of Controls" shown below with the most effective steps at the top and the least effective at the bottom. The high vaporization potential and flammability of chloroprene has significant implications for handling and storage operations in the occupational setting. Chloroprene should be stored in closed containers in a cool, well-ventilated area with the temperature no higher than . In addition, chloroprene has a