 Approximately 35 micrograms of beryllium is found in the average human body , an amount not considered harmful . Beryllium is chemically similar to magnesium and therefore can displace it from enzymes , which causes them to malfunction . Chronic berylliosis is a pulmonary and systemic granulomatous disease caused by inhalation of dust or fumes contaminated with beryllium ; either large amounts over a short time or small amounts over a long time can lead to this ailment . Symptoms of the disease can take up to five years to develop ; about a third of patients with it die and the survivors are left disabled . The International Agency for Research on Cancer ( IARC ) lists beryllium and beryllium compounds as Category 1 carcinogens . In the US , the Occupational Safety and Health Administration ( OSHA ) has designated a permissible exposure limit ( PEL ) in the workplace with a time @-@ weighted average ( TWA ) 0 @.@ 002 mg / m3 and a constant exposure limit of 0 @.@ 005 mg / m3 over 30 minutes , with a maximum peak limit of 0 @.@ 025 mg / m3 . The National Institute for Occupational Safety and Health ( NIOSH ) has set a recommended exposure limit ( REL ) of constant 0 @.@ 0005 mg / m3 . The IDLH ( immediately dangerous to life and health ) value is 4 mg / m3 . 
