ATE or Acute Toxicity Estimate is a calculation needed when authoring a Safety Data Sheet (SDS) for an untested mixture. Let’s face it, most mixtures are untested. 

What do you need to do? 

First, gather the oral and dermal LD50 values, then gather the inhalation (dust, mist, and vapor) LC50 values for each relevant ingredient in the mixture. Make sure the data is reliable and has been done with the correct species (rat or rabbit) and to the correct time period/test procedure. When doing ATE calculations, you must include Acute Toxicity values for category 5, even though OSHA does not include that as one of their building blocks. 

Once you have all of the data, then you can do the calculation for each route of entry. From OSHA Hazcom Appendix A for Health Hazards, here is the equation: 

Looks scary, doesn’t it? Once you put real numbers to it, it is just math (yep, scary). 

Let’s look at an example: 

Ingredient A                                                                               Ingredient B 

60%: 4000 mg/kg                                                                     40%: 1870 mg/kg 

Divide the concentration into the LD50 value 

60/4000=0.015                                                                         40/1870=0.021139037 

Next, add the two results together 

0.021139037 + 0.015 = 0.0361 

Finally divide 100 into the result. 

100/0.0361 = 2770.08 Acute Toxicity Category 5 (oral) 

Note that the equation is different if you have >10% unknown toxicity. That equation I will keep as a secret for now, lol. 

Need help with your calculations? Give us a call, our Regulatory Experts are here to help. 

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Karrie Ishmael, CDGP

Karrie Ishmael, CDGP

Karrie Ishmael has been with ICC since 1988. She has contributed to ICC's growth in various capacities, including customer service, sales, and marketing. In her current role as ICC's Senior Regulatory Expert and SDS author, Karrie conducts hazardous materials training classes in 49 CFR, IATA, IMDG, TDG along with OSHA and WHMIS hazard communication courses. When not training, she writes safety data sheets for customers to comply with North American and European requirements. She actively participates in many associations, including DGAC, COSTHA and is the former chair of SCHC’s OSHA Alliance Committee.