Robert D. Macomber Son
Pacific High School Bernordino, California
Chemistry Accidents in High School
The purpose of this study m s to determine the frequency of chemistry laboratory accidents in secondary schools and to identify some of the factors associated with the cause of the most serious ones. The data is derived from questionnaires received a t random from 148 public high schools in California. As defined in the study, serious accidents are those in which there is loss of school time of more than a day as a result of injury, or permanent disfigurement. Moderately serious accidents are those requiring more than minor first aid treatment but not causing permanent injury or loss of more than a day of school time. Minor accidents are those that can be adequately cared for by minor first aid treatment. The frequency of accidents was figured from 81 of the questionnaires; these included a listing of the total number of serious accidents and the enrollment in chemistry classes for the three school years from fall 1955 to spring 1958. They listed 13 individual serious accidents and 137 moderately serious for an average of 50 per year. Student enrollment in chemistry classes was 9123 per year in the 81 schools, a mean enrollment of about 113 students per school per year. There was one moderately serious or serious accident for every 182.4 students per school year in the sample studied or 0.61 accidents per school per year. Minor accidents are considerably more numerous. The data in the remainder of this study was given by the chemistry teachers concerning the most serious accident in the laboratory in each school during the three year period. In Table 1 the accidents have been grouped into six types. Explosions and phosphorus burns contributed the largest percentage of serious though there were only three of the latt,er. Over 80% of the explosions reported resulted in moderately serious or serious injuries. The types reported include explosions of organic substances (2) and of gas generators (5), and explosions resulting from the mixing of potassium chlorate with combustible materials (5), Table 1.
and from the heating of sealed glass tubes containing liquid (2). One implosion mas reported from vacuum in an ammonia fountain prepared from an Erlenmeyer flask rather than a round bottom flask. The questionnaire attempted to determine several factors relating to the type of laboratory work in which accidents occur. These include size of laboratory section per instructor, whpther the experiments were from published laboratory manuals, and actual student activity a t the time of the accident. Table 2 shows that the accident hazards increase as the size of the laboratory section increases. However only one respondent reported class size of less than ten students so the data for this group is not meaningful. Table 2. Distribution of 140 Laboratory Accidents by Seriousness and Class Size Per Instructor
Class sire
Number
Under 10 11 to 20 21 to 30 Over 30
1 9 95 35
Typeof amdent Burn (heat) Burn (acid br caustic) Explosions Cuts Poisoning Phosphorus
Per cent of the number of each type of accident Minor Moderate Serious
Number
Per cent
44
26.2
79.8
20.2
0.0
28 15 76 2 3
16.7 8.9 45.0 1.2 1.8
28.4 13.3 77.6 50.0 0.0
68.0 53.4 22.4 50.0 38.3
3.6 33.3 0.0 0.0 666
Includes one implosion.
0.7 .6.4 67.9 25.0
100 77.8 W.0 42.9
0.0 22.2 37.9 40.0
0.0 0.0 2.1 17.1
Accidents were still found to occur in schools using standard laboratory manuals. Kearly two-thirds of these were minor and were of the type in which the poor laboratory technique was responsible rather than any hazard present in the directions. Experiments prepared by the teacher or.student. did not show this same fact,or of safety (Table 3). This seems especially significant when project work is being so widely advocated in secondary school science. Included in Table 3 were experiments being performed outside of school by students but with the teachers' knowledge. Though this figure is not compared wit,h any number of successful experiments outside of school, within the limits of the available information it would seem that such experimentation is unwise. Table 3.
Distribution of 148 Laboratory Accidents by Type and Relative Seriousness
Per cent Per cent of the number of of accidents in each lab. size total Minor Moderate Serious
Preparation of Laboratory Experiments Related to Seriousness in 103 Accidents
Preparation of experiments
Number
Published manuals 75 Teacher pre~ared 15 Student prep in school 8 Student orco out of
Per cent
Per cent of the number of accidents for each type of preparation Minor Moderate Serious
73.0 14.5
62.7 40.0
34.7 53.4
2.6 6.6
7.7
37.5
37.5
25.0
Being performed outside of school but with the teachers' knowledge. Volume 38, Number 7, July 1961
/ 367
Table 4.
Actual Student Activity a t Time of Accident Related to Seriousness of Accident Per eent
Student activity
Numher
Following directions 77 On own seriously 21 "Horse play" 11
of total
70.5 19.3 10.2
Areident sorlousness
39.0 52.4 54.5
Serious Moderate Minor
59.7 33.3 18.2
1.3 14.3 27.3
I t can he assumed that few teachers would allow to remain in chemistry classes if they continued to play around in t,he laboratory rather than do serious work. For this reason the number of accidents in Table 4 where "horse play" is involved was only 10% of the total. From the data available however, it would seem t.hat the danger of injury is greater under this circumstance than when students are doing serions work. Of the accidents where "horse play" was involved, three of t,he students had previously been reprimanded for unsafe conduct. I n four cases the teacher had some feeling that the studentltwas an accident hazard, but the students involved in the remaining accidents were not considered t,o be in this cat,egory. The tabulated factors concerning t.he type of student involved in the accident,^ reflect his achievement in chemistry and his scientific inqnisitiveness as measured by teacher opinion. If only the serious and moderately serious accidents are considered, 40% occurred with st.udents above average in scient,ific inquisit,iveness. Nearly half of t.he students involved were average in inquisitiveness and only 11.5% were below average. Table 5 shows t.hat the pat,tern of accidents compared
/
Student's Achievement in Chemistry Compared with Seriousness of 126 Accidents
Per eent of the number of accidents for each type of student activity Minor Moderate Serious
student,^
368
Table 5.
Journol o f Chemicol Education
Per cent of the number of Per cent each category of seriousness Numof A-B C I)-F her total student student student 8 65 53
6.3 51.6 42.1
62.5 49.2 24.5
0.0 40.0 58.5
37.5 10.8 17.0
t.o the students' achievement in chemistry correlates with the above data. Average students were involved in 45.5% of the cases and the D-F students accounted for only 15.2% of t,he total on the 126 que~tionnaires xhere this seclion was rompleted. A follow-up let,ter t,o some of t,he t,earhers polled in this st,udy brought, out one significant item. Several said they finished their college chemistry courses n 3 h only vague ideas about the dangers involved in certain experiments or in the use of rertain chemicals. .Inother tearher, with an envious injury-free record, allows students to do laboratory work only after they h a v made a perfect score on an extensive safety exammation whirh has been t,horoughly studied in class. This seems an excellent idea and one to be highly rerommended. Conclusion
Arcidelits are most. likely to occur nit,h the capable, inquisit,ive student, allowed to use his initiative while the teacher supervises ot,hers. The stage is set by large laboratory sections, and perhaps by too easy availahilit,y of a few s~ubstancesthat may not he essential for maximum learning.
