DCHAS-L Archives, Aug 26, 2025 - Re: [DCHAS-L] Optimal Number of Students per TA/Instructor in General Chemistry Labs

We cap freshman labs at 24 students and organic at 16.

We are very fortunate here. Our dean was a former organic professor and our Provost, who just retired after many years, was a PChem professor. So, they fully understood the class size debate.

ACS offers some guidelines. Check out one of their notes about infrastructure on this page.

Creating a Safety Culture - American Chemical Society

Creating a Safety Culture Section 7 The preparation and development of undergraduate chemistry majors should reflect learning in both the classroom and laboratory and occur in a supportive and safe culture. Key aspects of the culture include a safety-first mindset, respect for chemical processes, and safe laboratory experimentation. A safety culture requires appropriate administrative support ...

www.acs.org

NSTA also has suggestions.

Liability of Science Educators for Laboratory Safety | NSTA

I can't recall the paper I read years ago which had a glitzy graph relating the number of incidents vs number of students. I shared it with a high school teacher as a simple way to get the point across to his administrators. Perhaps someone else can recall the publication.

From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**Princeton.EDU> on behalf of James Kaufman <jkaufman**At_Symbol_Here**LABSAFETYINSTITUTE.ORG>
Sent: Monday, August 25, 2025 4:18 PM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU <DCHAS-L**At_Symbol_Here**Princeton.EDU>
Subject: Re: [DCHAS-L] Optimal Number of Students per TA/Instructor in General Chemistry Labs

Pat ...

This is a recipe for disaster. It is sure starter fluid for a serious injury. It is a guaranteed big settlement in the plaintiff's favor. It completely disregards the recommendations of the American Chemical Society and Prudent Practices in the Laboratory. Need I say more.

And now ... I'll put my money where my mouth is ...

I will volunteer to teach our Leadership in Safety seminar for your senior administrators (President and his direct reports). I have done this previously for the Presidents of TAMU in both College Station and Laredo (and others throughout the United States and around the world).

Hoping to meet you at the seminar and not in court ... Jim

PS. LSI now has virtual lab inspections, safety program evaluations, document reviews, plus courses and seminars ... all virtual. And, a complimentary, updated version of our classic Laboratory Safety Guidelines is now available on our website ... https://www.labsafety.org/product/lab-safety-rules,

Plus ... be sure to take our Safer Science Self-Assessment to see how your organization stacks up! K-12: Safer Science Self-Assessment

Small University, College, Community College: Safer Science Self-Assessment

James A. Kaufman, PhD

Founder/President Emeritus

The Laboratory Safety Institute (LSI)

A Non-profit Educational Organization for Safety

in Academic, Industrial, and Government Laboratories

101 Oak Street, Wellesley, MA 02482 (MA Office)

(O) 508-647-1900 (C) 508-574-6264

Skype: labsafe; 508-401-7406 jkaufman**At_Symbol_Here**labsafety.org www.labsafety.org

Teach, Learn, and Practice Science Safely

On Mon, Aug 25, 2025 at 3:54 PM Leach, Patricia <Patricia.Leach**At_Symbol_Here**utdallas.edu> wrote:

Hello all,

We have had an explosion in the number of freshmen who are taking general chemistry this term, but funding has limited the number of TAs and instructors we have per lab room. The way the department has had to deal with this is to increase the number of students from 30 to 38 per section (limited by the Fire Marshall’s maximum occupancy of the rooms). They work in groups of 3 (not ideal at all). We have adjoining labs, so our shortage of instructors has been solved by having an instructor supervise two sections being held concurrently in a set of those labs. There is one TA per section.

In the past we have had 30 students (10 groups) supervised by a dedicated instructor (not working concurrent sections) and a TA, so about 15 students per person supervising. Now we can have as many as 38 students (13 groups) being supervised by one person at times, as the instructor moves between sections. I feel this is not safe.

What do people think is a safe ratio of supervising people to students (or student groups)?

Thanks,

Patricia Leach

Lab Manager

Department of Chemistry & Biochemistry

SLC 3.513

Office: 972-883-6583

Cell: 469-891-6426

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