Final answer:
The statement is false because the risk to workers from substance exposure is influenced by both the magnitude and the duration of the exposure.
Step-by-step explanation:
The degree of worker risk from the exposure to any given substance does depend on the magnitude and duration of exposure. Therefore, the correct answer is b) False. Occupational health and safety standards take into account both the concentration of a substance and the length of time a worker is exposed to it to determine the potential risk. High levels of exposure for extended periods increase the likelihood of adverse health effects.
Duration of exposure and magnitude of exposure are key factors in assessing workplace hazards. For instance, prolonged exposure at lower levels can be as harmful as short-term exposure at high levels, depending on the substance in question.