Campaigners say eggs contain toxic drugs
The campaign group believes lasalocid can cause heart contractions in humans and builds up in the body every time we eat eggs or chicken.
The Soil Association said the drug also has potent effects on the animals it is fed to and has called on the Food Standards Agency to ban it when it discusses the issue on Wednesday.
A spokesman for British Egg Industry Council said lasalocid was only found in eggs at very low levels and that consumers were not at any risk.
Lasalocid is given to chickens and turkeys in their feed as a preventative treatment against coccidiosis - an infectious disease which can damages the birds' intestines and cause illness and sometimes death.
Staple foods
Alison Craig, who carried out the Soil Association study, said low levels of lasalocid are present in 2.6% of all eggs and in 60% of quails' eggs.
Ms Craig said chickens not being treated against coccidiosis were also being exposed to the drug through cross-contaminated food, with potentially deadly effects.
"The lethal dose of these drugs is only two to three times the recommended dose," she said.
"In other words if you slightly over-do it you kill the animal."
Negligible risk
Andrew Joret from the British Egg Industry Council agreed that eggs should ideally be free of any residue, but the risk remained negligible.
He said: "The levels that have been found are actually very low levels for this product lasalocid.
"For example, if you take the highest residue that was discovered last year in one egg, you would have to eat 60 of those eggs every day to reach the acceptable daily intake for that particular product."
Ms Craig rejected the claim, arguing the recommended level was set more than 10 years ago and is currently under review by the European Commission.
She said: "What we are arguing for is that the drug should not be widely in use, that the cross-contamination problem has been known for years."