What might indicate a high LD50 for a substance?

A high LD50 value indicates that a substance requires a relatively large dose to be lethal to 50% of the test subjects, suggesting that the substance has a lower level of toxicity. This means that it is comparatively safer in terms of acute toxicity; therefore, it is less likely to cause harm at lower concentrations.

When discussing toxicity, it's essential to understand that a lower LD50 signifies higher toxicity because it takes a smaller dose to be lethal. In contrast, a high LD50 suggests that it takes a significant amount of the substance to achieve lethal effects, indicating that the substance is generally safer for use when proper application guidelines are followed.