no RADIOISOTOPES IN BIOLOGY AND AGRICULTURE 



17. Before the laboratory is left, the hands should be washed and 

 checked with a suitable low-level scanning instrument. 



In the Chemical Laboratory. It is perhaps not out of place to list a 

 few safety precautions which apply to all chemical-laboratory operations 

 but which may become of increasing importance when radioactive mate- 

 rials are involved (53) : 



1. Everyone in the laboratory should familiarize himself with the types, 

 locations, and use of fire extinguishers. Sand should be available for put- 

 ting out metal or metal hydride fires. 



2. When flammable solvents are in use, smoking and open flames are 

 forbidden. All electrical equipment should be sparkproof or explosion- 

 proof. A warning sign should be posted in the doorway. 



3. Flammable or highly volatile solvents should not be stored in any 

 laboratory room in greater than 10-gal quantities, with no more than 

 5 gal to a container. (This refers to the total quantity of all solvents in 

 the room.) 



4. Large quantities of flammable waste liquids that are not miscible 

 with water should be collected in closed metal cans. 



5. The contact of boiling, undiluted perchloric acid or hot vapors of 

 perchloric acid with organic matter or easily oxidized inorganic matter 

 results in serious explosions. Consequently such materials must be 

 destroyed before an evaporation with perchloric acid is carried out. 

 Evaporation should always be done in a hood with a good draft. Per- 

 chloric acid should never be fumed in hoods made of wood or similar 

 organic material. The quantity of perchloric acid stored in the labora- 

 tory should be kept to an absolute minimum and should be stored in such 

 a manner that there is no possibility of contact with organic materials. 



6. Concentrated acids and alkalies should be stored below bench-top 

 level in bottles set in lead or enamelware trays. 



7. Cleaning solution should be kept covered at all times. Location 

 near the sink should be avoided if possible. 



8. An intensive effort should be made to avoid mercury spills and to 

 keep mercury from collecting in various corners of the table. 



9. Both liquid oxygen and liquid nitrogen are often stored in the same 

 type of Dewar flask. Obviously care should be taken not to confuse the 

 two, since serious explosions may result from the contact of liquid oxygen 

 with organic matter. 



10. Safety glasses or shields should be worn for all vacuum-line work. 



11. All Dewar flasks should be wrapped with tape. 



12. All gas cylinders should be securely chained in place to avoid any 

 possibility of upsetting. 



13. Lead bricks and other heavy objects should not be stored in 

 elevated positions. 



